UserUtilities.xml

   1 <?xml version="1.0" encoding="utf-8"?>
   2 <chapter xmlns="http://docbook.org/ns/docbook"
   3 xmlns:xl="http://www.w3.org/1999/xlink" version="5.0" xml:lang="en-US"
   4 xml:id="userutilities"
   5 xmlns:xi="http://www.w3.org/2001/XInclude">
   6   <title xml:id="userutilities.title">User Utilities</title>
   7   <para>This chapter describes user utilities.</para>
   8   <section xml:id="dbdoclet.50438206_94597">
   9     <title>
  10       <indexterm>
  11         <primary>lfs</primary>
  12       </indexterm>
  13       <literal>lfs</literal>
  14     </title>
  15     <para>The
  16     <literal>lfs</literal> utility can be used for user configuration routines
  17     and monitoring.</para>
  18     <section remap="h5">
  19       <title>Synopsis</title>
  20       <screen>
  21 lfs
  22 lfs changelog [--follow] <replaceable>mdt_name</replaceable> [startrec [endrec]]
  23 lfs changelog_clear <replaceable>mdt_name id endrec</replaceable>
  24 lfs check <replaceable>mds|osts|servers</replaceable>
  25 lfs data_version [-nrw] <replaceable>filename</replaceable>
  26 lfs df [-i] [-h] [--pool]-p <replaceable>fsname</replaceable>[.<replaceable>pool</replaceable>] [<replaceable>path</replaceable>] [--lazy]
  27 lfs find [[!] --atime|-A [-+]N] [[!] --mtime|-M [-+]N]
  28          [[!] --ctime|-C [-+]N] [--maxdepth|-D N] [--name|-n <replaceable>pattern</replaceable>]
  29          [--print|-p] [--print0|-P] [[!] --obd|-O <replaceable>ost_name</replaceable>[,<replaceable>ost_name...</replaceable>]]
  30          [[!] --size|-S [+-]N[kMGTPE]] --type |-t {bcdflpsD}]
  31          [[!] --gid|-g|--group|-G <replaceable>gname|gid</replaceable>]
  32          [[!] --uid|-u|--user|-U <replaceable>uname|uid</replaceable>]
  33          <replaceable>dirname|filename</replaceable>
  34 lfs getname [-h]|[path...]
  35 lfs getstripe [--obd|-O <replaceable>ost_name</replaceable>] [--quiet|-q] [--verbose|-v]
  36               [--stripe-count|-c] [--stripe-index|-i]
  37               [--stripe-size|-s] [--pool|-p] [--directory|-d]
  38               [--mdt-index|-M] [--recursive|-r] [--raw|-R]
  39               [--layout|-L]
  40               <replaceable>dirname|filename</replaceable> ...
  41 lfs setstripe [--size|-s stripe_size] [--stripe-count|-c <replaceable>stripe_count</replaceable>]
  42               [--overstripe-count|-C <replaceable>stripe_count</replaceable>]
  43               [--stripe-index|-i <replaceable>start_ost_index</replaceable>]
  44               [--ost-list|-o <replaceable>ost_indicies</replaceable>]
  45               [--pool|-p <replaceable>pool</replaceable>]
  46               <replaceable>dirname|filename</replaceable>
  47 lfs setstripe -d <replaceable>dir</replaceable>
  48 lfs osts [path]
  49 lfs pool_list <replaceable>filesystem</replaceable>[.<replaceable>pool</replaceable>]| <replaceable>pathname</replaceable>
  50 lfs quota [-q] [-v] [-h] [-o <replaceable>obd_uuid</replaceable>|-I <replaceable>ost_idx</replaceable>|-i <replaceable>mdt_idx</replaceable>]
  51           [-u <replaceable>username|uid|-g</replaceable> <replaceable>group|gid</replaceable>|-p <replaceable>projid</replaceable>] <replaceable>/mount_point</replaceable>
  52 lfs quota -t -u|-g|-p <replaceable>/mount_point</replaceable>
  53 lfs quotacheck [-ug] <replaceable>/mount_point</replaceable>
  54 lfs quotachown [-i] <replaceable>/mount_point</replaceable>
  55 lfs quotainv [-ug] [-f] <replaceable>/mount_point</replaceable>
  56 lfs quotaon [-ugf] <replaceable>/mount_point</replaceable>
  57 lfs quotaoff [-ug] <replaceable>/mount_point</replaceable>
  58 lfs setquota {-u|--user|-g|--group|-p|--project} <replaceable>uname|uid|gname|gid|projid</replaceable>
  59              [--block-softlimit <replaceable>block_softlimit</replaceable>]
  60              [--block-hardlimit <replaceable>block_hardlimit</replaceable>]
  61              [--inode-softlimit <replaceable>inode_softlimit</replaceable>]
  62              [--inode-hardlimit <replaceable>inode_hardlimit</replaceable>]
  63              <replaceable>/mount_point</replaceable>
  64 lfs setquota -u|--user|-g|--group|-p|--project <replaceable>uname|uid|gname|gid|projid</replaceable>
  65              [-b <replaceable>block_softlimit</replaceable>] [-B <replaceable>block_hardlimit</replaceable>]
  66              [-i <replaceable>inode-softlimit</replaceable>] [-I <replaceable>inode_hardlimit</replaceable>]
  67              <replaceable>/mount_point</replaceable>
  68 lfs setquota -t -u|-g|-p [--block-grace <replaceable>block_grace</replaceable>]
  69              [--inode-grace <replaceable>inode_grace</replaceable>]
  70              <replaceable>/mount_point</replaceable>
  71 lfs setquota -t -u|-g|-p [-b <replaceable>block_grace</replaceable>] [-i <replaceable>inode_grace</replaceable>]
  72              <replaceable>/mount_point</replaceable>
  73 lfs help
  74 </screen>
  75       <note>
  76         <para>In the above example, the
  77         <literal>
  78           <replaceable>/mount_point</replaceable>
  79         </literal> parameter refers to the mount point of the Lustre file
  80         system.</para>
  81       </note>
  82       <note>
  83         <para>The old lfs quota output was very detailed and contained
  84         cluster-wide quota statistics (including cluster-wide limits for a
  85         user/group and cluster-wide usage for a user/group), as well as
  86         statistics for each MDS/OST. Now,
  87         <literal>lfs quota</literal> has been updated to provide only
  88         cluster-wide statistics, by default. To obtain the full report of
  89         cluster-wide limits, usage and statistics, use the
  90         <literal>-v</literal> option with
  91         <literal>lfs quota</literal>.</para>
  92       </note>
  93     </section>
  94     <section remap="h5">
  95       <title>Description</title>
  96       <para>The
  97       <literal>lfs</literal> utility is used to create a new file with a
  98       specific striping pattern, determine the default striping pattern, gather
  99       the extended attributes (object numbers and location) for a specific
 100       file, find files with specific attributes, list OST information or set
 101       quota limits. It can be invoked interactively without any arguments or in
 102       a non-interactive mode with one of the supported arguments.</para>
 103     </section>
 104     <section remap="h5">
 105       <title>Options</title>
 106       <para>The various
 107       <literal>lfs</literal> options are listed and described below. For a
 108       complete list of available options, type help at the
 109       <literal>lfs</literal> prompt.</para>
 110       <informaltable frame="all">
 111         <tgroup cols="3">
 112           <colspec colname="c1" colwidth="20*" />
 113           <colspec colname="c2" colwidth="30*" />
 114           <colspec colname="c3" colwidth="50*" />
 115           <thead>
 116             <row>
 117               <entry nameend="c2" namest="c1">
 118                 <para>
 119                   <emphasis role="bold">Option</emphasis>
 120                 </para>
 121               </entry>
 122               <entry>
 123                 <para>
 124                   <emphasis role="bold">Description</emphasis>
 125                 </para>
 126               </entry>
 127             </row>
 128           </thead>
 129           <tbody>
 130             <row>
 131               <entry nameend="c2" namest="c1">
 132                 <para>
 133                   <literal>changelog</literal>
 134                 </para>
 135               </entry>
 136               <entry>
 137                 <para>Shows the metadata changes on an MDT. Start and end
 138                 points are optional. The
 139                 <literal>--follow</literal> option blocks on new changes; this
 140                 option is only valid when run directly on the MDT node.</para>
 141               </entry>
 142             </row>
 143             <row>
 144               <entry nameend="c2" namest="c1">
 145                 <para>
 146                   <literal>changelog_clear</literal>
 147                 </para>
 148               </entry>
 149               <entry>
 150                 <para>Indicates that changelog records previous to
 151                 <literal>
 152                   <replaceable>endrec</replaceable>
 153                 </literal> are no longer of interest to a particular consumer
 154                 <literal>
 155                   <replaceable>id</replaceable>
 156                 </literal>, potentially allowing the MDT to free up disk space.
 157                 An
 158                 <literal>
 159                   <replaceable>endrec</replaceable>
 160                 </literal> of 0 indicates the current last record. Changelog
 161                 consumers must be registered on the MDT node using
 162                 <literal>lctl</literal>.</para>
 163               </entry>
 164             </row>
 165             <row>
 166               <entry nameend="c2" namest="c1">
 167                 <literal>check</literal>
 168               </entry>
 169               <entry>
 170                 <para>Displays the status of MDS or OSTs (as specified in the
 171                 command) or all servers (MDS and OSTs).</para>
 172               </entry>
 173             </row>
 174             <row>
 175               <entry nameend="c2" namest="c1">
 176                 <para>
 177                   <literal>data_version [-nrw]
 178                   <replaceable>filename</replaceable></literal>
 179                 </para>
 180               </entry>
 181               <entry>
 182                 <para>Displays the current version of file data. If
 183                 <literal>-n</literal> is specified, the data version is read
 184                 without taking a lock. As a consequence, the data version could
 185                 be outdated if there are dirty caches on filesystem clients, but
 186                 this option will not force data flushes and has less of an
 187                 impact on the filesystem. If <literal>-r</literal> is specified,
 188                 the data version is read after dirty pages on clients are
 189                 flushed. If <literal>-w</literal> is specified, the data version
 190                 is read after all caching pages on clients are flushed.
 191                 </para>
 192                 <para>
 193                 Even with <literal>-r</literal> or <literal>-w</literal>, race
 194                 conditions are possible and the data version should be checked
 195                 before and after an operation to be confident the data did not
 196                 change during it.
 197                 </para>
 198                 <para>
 199                 The  data  version is the sum of the last committed transaction
 200                 numbers of all data objects of a file. It is used by HSM policy
 201                 engines for verifying that file data has not been changed during
 202                 an archive operation or before a release operation, and by OST
 203                 migration, primarily for verifying that file data has not been
 204                 changed during a data copy, when done in non-blocking mode.
 205                 </para>
 206               </entry>
 207             </row>
 208             <row>
 209               <entry nameend="c2" namest="c1">
 210                 <literal>df [-i] [-h] [--pool|-p
 211                 <replaceable>fsname</replaceable>[.
 212                 <replaceable>pool</replaceable>] [
 213                 <replaceable>path</replaceable>] [--lazy]</literal>
 214               </entry>
 215               <entry>
 216                 <para>Use
 217                 <literal>-i</literal> to report file system disk space usage or
 218                 inode usage of each MDT or OST or, if a pool is specified with
 219                 the
 220                 <literal>-p</literal> option, a subset of OSTs.</para>
 221                 <para>By default, the usage of all mounted Lustre file systems
 222                 is reported. If the
 223                 <literal>path</literal> option is included, only the usage for
 224                 the specified file system is reported. If the
 225                 <literal>-h</literal> option is included, the output is printed
 226                 in human-readable format, using SI base-2 suffixes for
 227                 <emphasis role="bold">M</emphasis>ega-,
 228                 <emphasis role="bold">G</emphasis>iga-,
 229                 <emphasis role="bold">T</emphasis>era-,
 230                 <emphasis role="bold">P</emphasis>eta-, or
 231                 <emphasis role="bold">E</emphasis>xabytes.</para>
 232                 <para>If the
 233                 <literal>--lazy</literal> option is specified, any OST that is
 234                 currently disconnected from the client will be skipped. Using
 235                 the
 236                 <literal>--lazy</literal> option prevents the
 237                 <literal>df</literal> output from being blocked when an OST is
 238                 offline. Only the space on the OSTs that can currently be
 239                 accessed are returned. The
 240                 <literal>llite.*.lazystatfs</literal> tunable can be enabled to
 241                 make this the default behaviour for all
 242                 <literal>statfs()</literal> operations.</para>
 243               </entry>
 244             </row>
 245             <row>
 246               <entry nameend="c2" namest="c1">
 247                 <para>
 248                   <literal>find</literal>
 249                 </para>
 250               </entry>
 251               <entry>
 252                 <para>Searches the directory tree rooted at the given
 253                 directory/filename for files that match the given
 254                 parameters.</para>
 255                 <para>Using
 256                 <literal>!</literal> before an option negates its meaning (files
 257                 NOT matching the parameter). Using
 258                 <literal>+</literal> before a numeric value means files with the
 259                 parameter OR MORE. Using
 260                 <literal>-</literal> before a numeric value means files with the
 261                 parameter OR LESS.</para>
 262               </entry>
 263             </row>
 264             <row>
 265               <entry />
 266               <entry>
 267                 <literal>--atime</literal>
 268               </entry>
 269               <entry>
 270                 <para>File was last accessed N*24 hours ago. (There is no
 271                 guarantee that
 272                 <literal>atime</literal> is kept coherent across the
 273                 cluster.)</para>
 274                 <para>OSTs store a transient
 275                 <literal>atime</literal> that is updated when clients do read
 276                 requests. Permanent
 277                 <literal>atime</literal> is written to the MDS when the file is
 278                 closed. However, on-disk atime is only updated if it is more
 279                 than 60 seconds old (
 280                 <literal>/proc/fs/lustre/mds/*/max_atime_diff</literal>). The
 281                 Lustre software considers the latest
 282                 <literal>atime</literal> from all OSTs. If a
 283                 <literal>setattr</literal> is set by user, then it is updated on
 284                 both the MDS and OST, allowing the
 285                 <literal>atime</literal> to go backward.</para>
 286               </entry>
 287             </row>
 288             <row>
 289               <entry>
 290                 <para>&#160;</para>
 291               </entry>
 292               <entry>
 293                 <para>
 294                   <literal>--ctime</literal>
 295                 </para>
 296               </entry>
 297               <entry>
 298                 <para>File status was last changed N*24 hours ago.</para>
 299               </entry>
 300             </row>
 301             <row>
 302               <entry>
 303                 <para>&#160;</para>
 304               </entry>
 305               <entry>
 306                 <para>
 307                   <literal>--mtime</literal>
 308                 </para>
 309               </entry>
 310               <entry>
 311                 <para>File data was last modified N*24 hours ago.</para>
 312               </entry>
 313             </row>
 314             <row>
 315               <entry>
 316                 <para>&#160;</para>
 317               </entry>
 318               <entry>
 319                 <para>
 320                   <literal>--obd</literal>
 321                 </para>
 322               </entry>
 323               <entry>
 324                 <para>File has an object on a specific OST(s).</para>
 325               </entry>
 326             </row>
 327             <row>
 328               <entry>
 329                 <para>&#160;</para>
 330               </entry>
 331               <entry>
 332                 <para>
 333                   <literal>--size</literal>
 334                 </para>
 335               </entry>
 336               <entry>
 337                 <para>File has a size in bytes, or kilo-, Mega-, Giga-, Tera-,
 338                 Peta- or Exabytes if a suffix is given.</para>
 339               </entry>
 340             </row>
 341             <row>
 342               <entry>
 343                 <para>&#160;</para>
 344               </entry>
 345               <entry>
 346                 <para>
 347                   <literal>--type</literal>
 348                 </para>
 349               </entry>
 350               <entry>
 351                 <para>File has the type - block, character, directory, pipe,
 352                 file, symlink, socket or door (used in Solaris operating
 353                 system).</para>
 354               </entry>
 355             </row>
 356             <row>
 357               <entry>
 358                 <para>&#160;</para>
 359               </entry>
 360               <entry>
 361                 <para>
 362                   <literal>--uid</literal>
 363                 </para>
 364               </entry>
 365               <entry>
 366                 <para>File has a specific numeric user ID.</para>
 367               </entry>
 368             </row>
 369             <row>
 370               <entry>
 371                 <para>&#160;</para>
 372               </entry>
 373               <entry>
 374                 <para>
 375                   <literal>--user</literal>
 376                 </para>
 377               </entry>
 378               <entry>
 379                 <para>File owned by a specific user (numeric user ID
 380                 allowed).</para>
 381               </entry>
 382             </row>
 383             <row>
 384               <entry>
 385                 <para>&#160;</para>
 386               </entry>
 387               <entry>
 388                 <para>
 389                   <literal>--gid</literal>
 390                 </para>
 391               </entry>
 392               <entry>
 393                 <para>File has a specific group ID.</para>
 394               </entry>
 395             </row>
 396             <row>
 397               <entry>
 398                 <para>&#160;</para>
 399               </entry>
 400               <entry>
 401                 <para>
 402                   <literal>--group</literal>
 403                 </para>
 404               </entry>
 405               <entry>
 406                 <para>File belongs to a specific group (numeric group ID
 407                 allowed).</para>
 408               </entry>
 409             </row>
 410             <row>
 411               <entry>
 412                 <para>&#160;</para>
 413               </entry>
 414               <entry>
 415                 <para>-
 416                 <literal>-maxdepth</literal></para>
 417               </entry>
 418               <entry>
 419                 <para>Limits find to descend at most N levels of the directory
 420                 tree.</para>
 421               </entry>
 422             </row>
 423             <row>
 424               <entry>
 425                 <para>&#160;</para>
 426               </entry>
 427               <entry>
 428                 <para>
 429                 <literal>--print</literal>/
 430                 <literal>--print0</literal></para>
 431               </entry>
 432               <entry>
 433                 <para>Prints the full filename, followed by a new line or NULL
 434                 character correspondingly.</para>
 435               </entry>
 436             </row>
 437             <row>
 438               <entry nameend="c2" namest="c1">
 439                 <para>
 440                   <literal>osts [path]</literal>
 441                 </para>
 442               </entry>
 443               <entry>
 444                 <para>Lists all OSTs for the file system. If a path located on
 445                 a mounted Lustre file system is specified, then only OSTs
 446                 belonging to this file system are displayed.</para>
 447               </entry>
 448             </row>
 449             <row>
 450               <entry nameend="c2" namest="c1">
 451                 <para>
 452                   <literal>getname [path...]</literal>
 453                 </para>
 454               </entry>
 455               <entry>
 456                 <para>List each Lustre file system instance associated with
 457                 each Lustre mount point. If no path is specified, all Lustre
 458                 mount points are interrogated. If a list of paths is provided,
 459                 the instance of each path is provided. If the path is not a
 460                 Lustre instance 'No such device' is returned.</para>
 461               </entry>
 462             </row>
 463             <row>
 464               <entry nameend="c2" namest="c1">
 465                 <para>
 466                   <literal>getstripe</literal>
 467                 </para>
 468               </entry>
 469               <entry>
 470                 <para>Lists striping information for a given filename or
 471                 directory. By default, the stripe count, stripe size and offset
 472                 are returned.</para>
 473                 <para>If you only want specific striping information, then the
 474                 options of
 475                 <literal>--stripe-count</literal>,
 476                 <literal>--stripe-size</literal>,
 477                 <literal>--stripe-index</literal>,
 478                 <literal>--layout</literal>, or
 479                 <literal>--pool</literal> plus various combinations of these
 480                 options can be used to retrieve specific information.</para>
 481                 <para>If the
 482                 <literal>--raw</literal> option is specified, the stripe
 483                 information is printed without substituting the file system
 484                 default values for unspecified fields. If the striping EA is
 485                 not set, 0, 0, and -1 will be printed for the stripe count,
 486                 size, and offset respectively.</para>
 487                 <para>The <literal>--mdt-index</literal> prints the index of
 488                 the MDT for a given directory. See
 489                 <xref linkend="lustremaint.rmremotedir" />.</para>
 490               </entry>
 491             </row>
 492             <row>
 493               <entry>
 494                 <para>&#160;</para>
 495               </entry>
 496               <entry>
 497                 <para>
 498                   <literal>--obd
 499                   <replaceable>ost_name</replaceable></literal>
 500                 </para>
 501               </entry>
 502               <entry>
 503                 <para>Lists files that have an object on a specific OST.</para>
 504               </entry>
 505             </row>
 506             <row>
 507               <entry>
 508                 <para>&#160;</para>
 509               </entry>
 510               <entry>
 511                 <para>
 512                   <literal>--quiet</literal>
 513                 </para>
 514               </entry>
 515               <entry>
 516                 <para>Lists details about the file's object ID
 517                 information.</para>
 518               </entry>
 519             </row>
 520             <row>
 521               <entry>
 522                 <para>&#160;</para>
 523               </entry>
 524               <entry>
 525                 <para>
 526                   <literal>--verbose</literal>
 527                 </para>
 528               </entry>
 529               <entry>
 530                 <para>Prints additional striping information.</para>
 531               </entry>
 532             </row>
 533             <row>
 534               <entry>
 535                 <para>&#160;</para>
 536               </entry>
 537               <entry>
 538                 <para>
 539                   <literal>--stripe-count</literal>
 540                 </para>
 541               </entry>
 542               <entry>
 543                 <para>Lists the stripe count (how many OSTs to use).</para>
 544               </entry>
 545             </row>
 546             <row>
 547               <entry>
 548                 <para>&#160;</para>
 549               </entry>
 550               <entry>
 551                 <para>
 552                   <literal>--index</literal>
 553                 </para>
 554               </entry>
 555               <entry>
 556                 <para>Lists the index for each OST in the file system.</para>
 557               </entry>
 558             </row>
 559             <row>
 560               <entry>
 561                 <para>&#160;</para>
 562               </entry>
 563               <entry>
 564                 <para>
 565                   <literal>--offset</literal>
 566                 </para>
 567               </entry>
 568               <entry>
 569                 <para>Lists the OST index on which file striping starts.</para>
 570               </entry>
 571             </row>
 572             <row>
 573               <entry>
 574                 <para>&#160;</para>
 575               </entry>
 576               <entry>
 577                 <para>
 578                   <literal>--pool</literal>
 579                 </para>
 580               </entry>
 581               <entry>
 582                 <para>Lists the pools to which a file belongs.</para>
 583               </entry>
 584             </row>
 585             <row>
 586               <entry>
 587                 <para>&#160;</para>
 588               </entry>
 589               <entry>
 590                 <para>
 591                   <literal>--size</literal>
 592                 </para>
 593               </entry>
 594               <entry>
 595                 <para>Lists the stripe size (how much data to write to one OST
 596                 before moving to the next OST).</para>
 597               </entry>
 598             </row>
 599             <row>
 600               <entry>
 601                 <para>&#160;</para>
 602               </entry>
 603               <entry>
 604                 <para>
 605                   <literal>--directory</literal>
 606                 </para>
 607               </entry>
 608               <entry>
 609                 <para>Lists entries about a specified directory instead of its
 610                 contents (in the same manner as
 611                 <literal>ls -d</literal>).</para>
 612               </entry>
 613             </row>
 614             <row>
 615               <entry>
 616                 <para>&#160;</para>
 617               </entry>
 618               <entry>
 619                 <para>
 620                   <literal>--recursive</literal>
 621                 </para>
 622               </entry>
 623               <entry>
 624                 <para>Recurses into all sub-directories.</para>
 625               </entry>
 626             </row>
 627             <row>
 628               <entry nameend="c2" namest="c1">
 629                 <para>
 630                   <literal>setstripe</literal>
 631                 </para>
 632               </entry>
 633               <entry>
 634                 <para>Create new files with a specific file layout (stripe
 635                 pattern) configuration.
 636                 <footnote>
 637                   <para>The file cannot exist prior to using
 638                   <literal>setstripe</literal>. A directory must exist prior to
 639                   using
 640                   <literal>setstripe</literal>.</para>
 641                 </footnote></para>
 642               </entry>
 643             </row>
 644             <row>
 645               <entry>
 646                 <para>&#160;</para>
 647               </entry>
 648               <entry>
 649                 <para>
 650                   <literal>--stripe-count stripe_cnt</literal>
 651                 </para>
 652               </entry>
 653               <entry>
 654                 <para>Number of OSTs over which to stripe a file. A
 655                 <literal>stripe_cnt</literal> of 0 uses the file system-wide
 656                 default stripe count (default is 1). A
 657                 <literal>stripe_cnt</literal> of -1 stripes over all available
 658                 OSTs.</para>
 659               </entry>
 660             </row>
 661             <row>
 662               <entry>
 663                 <para>&#160;</para>
 664               </entry>
 665               <entry>
 666                 <para>
 667                   <literal>--overstripe-count stripe_cnt</literal>
 668                 </para>
 669               </entry>
 670               <entry>
 671                 <para>The same as --stripe-count, but allows overstriping,
 672                 which will place more than one stripe per OST if
 673                 <literal>stripe_cnt</literal> is greater than the number of
 674                 OSTs. Overstriping is useful for matching the number of stripes
 675                 to the number of processes, or with very fast OSTs, where one
 676                 stripe per OST is not enough to get full performance.</para>
 677               </entry>
 678             </row>
 679             <row>
 680               <entry>
 681                 <para>&#160;</para>
 682               </entry>
 683               <entry>
 684                 <para>
 685                 <literal>--size stripe_size</literal>
 686                 <footnote>
 687                   <para>The default stripe-size is 0. The default start-ost is
 688                   -1. Do NOT confuse them! If you set start-ost to 0, all new
 689                   file creations occur on OST 0 (seldom a good idea).</para>
 690                 </footnote>&#160;</para>
 691               </entry>
 692               <entry>
 693                 <para>Number of bytes to store on an OST before moving to the
 694                 next OST. A stripe_size of 0 uses the file system's default
 695                 stripe size, (default is 1 MB). Can be specified with
 696                 <emphasis role="bold">k</emphasis>(KB),
 697                 <emphasis role="bold">m</emphasis>(MB), or
 698                 <emphasis role="bold">g</emphasis>(GB), respectively.</para>
 699               </entry>
 700             </row>
 701             <row>
 702               <entry>
 703                 <para>&#160;</para>
 704               </entry>
 705               <entry>
 706                 <para>
 707                   <literal>--stripe-index start_ost_index</literal>
 708                 </para>
 709               </entry>
 710               <entry>
 711                 <para>The OST index (base 10, starting at 0) on which to start
 712                 striping for this file. A start_ost_index value of -1 allows
 713                 the MDS to choose the starting index. This is the default
 714                 value, and it means that the MDS selects the starting OST as it
 715                 wants. We strongly recommend selecting this default, as it
 716                 allows space and load balancing to be done by the MDS as
 717                 needed. The
 718                 <literal>start_ost_index</literal> value has no relevance on
 719                 whether the MDS will use round-robin or QoS weighted allocation
 720                 for the remaining stripes in the file.</para>
 721               </entry>
 722             </row>
 723             <row>
 724               <entry>
 725                 <para>&#160;</para>
 726               </entry>
 727               <entry>
 728                 <para>
 729                   <literal>--ost-index ost_indices</literal>
 730                 </para>
 731               </entry>
 732               <entry>
 733                                 <para>This option is used to specify the exact stripe
 734                 layout on the the file system. <literal>ost_indices</literal>
 735                 is a list of OSTs referenced by their indices and index ranges
 736                 separated by commas, e.g. <literal>1,2-4,7</literal>.</para>
 737               </entry>
 738             </row>
 739             <row>
 740               <entry>
 741                 <para>&#160;</para>
 742               </entry>
 743               <entry>
 744                 <para>
 745                   <literal>--pool
 746                   <replaceable>pool</replaceable></literal>
 747                 </para>
 748               </entry>
 749               <entry>
 750                 <para>Name of the pre-defined pool of OSTs (see
 751                 <xref linkend="dbdoclet.50438219_38274" />) that will be used
 752                 for striping. The
 753                 <literal>stripe_cnt</literal>,
 754                 <literal>stripe_size</literal> and
 755                 <literal>start_ost</literal> values are used as well. The
 756                 start-ost value must be part of the pool or an error is
 757                 returned.</para>
 758               </entry>
 759             </row>
 760             <row>
 761               <entry nameend="c2" namest="c1">
 762                 <para>
 763                   <literal>setstripe -d</literal>
 764                 </para>
 765               </entry>
 766               <entry>
 767                 <para>Deletes default striping on the specified
 768                 directory.</para>
 769               </entry>
 770             </row>
 771             <row>
 772               <entry nameend="c2" namest="c1">
 773                 <para>
 774                   <literal>pool_list {filesystem}[.poolname]|{pathname}</literal>
 775                 </para>
 776               </entry>
 777               <entry>
 778                 <para>Lists pools in the file system or pathname, or OSTs in
 779                 the file system's pool.</para>
 780               </entry>
 781             </row>
 782             <row>
 783               <entry nameend="c2" namest="c1">
 784                 <para>
 785                   <literal>quota [-q] [-v] [-o
 786                   <replaceable>obd_uuid</replaceable>|-i
 787                   <replaceable>mdt_idx</replaceable>|-I
 788                   <replaceable>ost_idx</replaceable>] [-u|-g|-p
 789                   <replaceable>uname|uid|gname|gid|projid]</replaceable>
 790                   <replaceable>/mount_point</replaceable></literal>
 791                 </para>
 792                 <para>&#160;</para>
 793               </entry>
 794               <entry>
 795                 <para>Displays disk usage and limits, either for the full file
 796                 system or for objects on a specific OBD. A user or group name
 797                 or an usr, group and project ID can be specified. If all user,
 798                 group project ID are omitted, quotas for the current UID/GID
 799                 are shown. The <literal>-q</literal> option disables printing
 800                 of additional descriptions (including column titles). It fills
 801                 in blank spaces in the
 802                 <literal>grace</literal> column with zeros (when there is no
 803                 grace period set), to ensure that the number of columns is
 804                 consistent. The
 805                 <literal>-v</literal> option provides more verbose (per-OBD
 806                 statistics) output.</para>
 807               </entry>
 808             </row>
 809             <row>
 810               <entry nameend="c2" namest="c1">
 811                 <para>
 812                   <literal>quota -t
 813                   <replaceable>-u|-g|-p</replaceable>
 814                   <replaceable>/mount_point</replaceable></literal>
 815                 </para>
 816               </entry>
 817               <entry>
 818                 <para>Displays block and inode grace times for user (
 819                 <literal>-u</literal>) or group (
 820                 <literal>-g</literal>) or project (
 821                 <literal>-p</literal>) quotas.</para>
 822               </entry>
 823             </row>
 824             <row>
 825               <entry nameend="c2" namest="c1">
 826                 <para>
 827                   <literal>quotachown</literal>
 828                 </para>
 829               </entry>
 830               <entry>
 831                 <para>Changes the file's owner and group on OSTs of the
 832                 specified file system.</para>
 833               </entry>
 834             </row>
 835             <row>
 836               <entry nameend="c2" namest="c1">
 837                 <para>
 838                   <literal>quotacheck [-ugf]
 839                   <replaceable>/mount_point</replaceable></literal>
 840                 </para>
 841               </entry>
 842               <entry>
 843                 <para>Scans the specified file system for disk usage, and
 844                 creates or updates quota files. Options specify quota for users
 845                 (
 846                 <literal>-u</literal>), groups (
 847                 <literal>-g</literal>), and force (
 848                 <literal>-f</literal>).</para>
 849               </entry>
 850             </row>
 851             <row>
 852               <entry nameend="c2" namest="c1">
 853                 <para>
 854                   <literal>quotaon [-ugf]
 855                   <replaceable>/mount_point</replaceable></literal>
 856                 </para>
 857               </entry>
 858               <entry>
 859                 <para>Turns on file system quotas. Options specify quota for
 860                 users (
 861                 <literal>-u</literal>), groups (
 862                 <literal>-g</literal>), and force (
 863                 <literal>-f</literal>).</para>
 864               </entry>
 865             </row>
 866             <row>
 867               <entry nameend="c2" namest="c1">
 868                 <para>
 869                   <literal>quotaoff [-ugf]
 870                   <replaceable>/mount_point</replaceable></literal>
 871                 </para>
 872               </entry>
 873               <entry>
 874                 <para>Turns off file system quotas. Options specify quota for
 875                 users (
 876                 <literal>-u</literal>), groups (
 877                 <literal>-g</literal>), and force (
 878                 <literal>-f</literal>).</para>
 879               </entry>
 880             </row>
 881             <row>
 882               <entry nameend="c2" namest="c1">
 883                 <para>
 884                   <literal>quotainv [-ug] [-f]
 885                   <replaceable>/mount_point</replaceable></literal>
 886                 </para>
 887               </entry>
 888               <entry>
 889                 <para>Clears quota files (administrative quota files if used
 890                 without
 891                 <literal>-f</literal>, operational quota files otherwise), all
 892                 of their quota entries for users (
 893                 <literal>-u</literal>) or groups (
 894                 <literal>-g</literal>). After running
 895                 <literal>quotainv</literal>, you must run
 896                 <literal>quotacheck</literal> before using quotas.</para>
 897                 <caution>
 898                   <para>Use extreme caution when using this command; its
 899                   results cannot be undone.</para>
 900                 </caution>
 901               </entry>
 902             </row>
 903             <row>
 904               <entry nameend="c2" namest="c1">
 905                 <para>
 906                   <literal>setquota {-u|-g|-p
 907                   <replaceable>uname|uid|gname|gid|projid}</replaceable>
 908                   [--block-softlimit
 909                   <replaceable>block_softlimit</replaceable>]
 910                   [--block-hardlimit
 911                   <replaceable>block_hardlimit</replaceable>]
 912                   [--inode-softlimit
 913                   <replaceable>inode_softlimit</replaceable>]
 914                   [--inode-hardlimit
 915                   <replaceable>inode_hardlimit</replaceable>]
 916                   <replaceable>/mount_point</replaceable></literal>
 917                 </para>
 918               </entry>
 919               <entry>
 920                 <para>Sets file system quotas for users, groups or one project.
 921                 Limits can be specified with
 922                 <literal>--{block|inode}-{softlimit|hardlimit}</literal> or
 923                 their short equivalents
 924                 <literal>-b</literal>,
 925                 <literal>-B</literal>,
 926                 <literal>-i</literal>,
 927                 <literal>-I</literal>. Users can set 1, 2, 3 or 4 limits.
 928                 <footnote>
 929                   <para>The old
 930                   <literal>setquota</literal> interface is supported, but it may
 931                   be removed in a future Lustre software release.</para>
 932                 </footnote>Also, limits can be specified with special suffixes,
 933                 -b, -k, -m, -g, -t, and -p to indicate units of 1, 2^10, 2^20,
 934                 2^30, 2^40 and 2^50, respectively. By default, the block limits
 935                 unit is 1 kilobyte (1,024), and block limits are always
 936                 kilobyte-grained (even if specified in bytes). See
 937                 <xref linkend="dbdoclet.50438206_11903" />.</para>
 938               </entry>
 939             </row>
 940             <row>
 941               <entry nameend="c2" namest="c1">
 942                 <para>
 943                   <literal>setquota -t -u|-g|-p [--block-grace
 944                   <replaceable>block_grace</replaceable>] [--inode-grace
 945                   <replaceable>inode_grace</replaceable>]
 946                   <replaceable>/mount_point</replaceable></literal>
 947                 </para>
 948               </entry>
 949               <entry>
 950                 <para>Sets the file system quota grace times for users or
 951                 groups. Grace time is specified in '
 952                 <literal>XXwXXdXXhXXmXXs</literal>' format or as an integer
 953                 seconds value. See
 954                 <xref linkend="dbdoclet.50438206_11903" />.</para>
 955               </entry>
 956             </row>
 957             <row>
 958               <entry nameend="c2" namest="c1">
 959                 <para>
 960                   <literal>help</literal>
 961                 </para>
 962               </entry>
 963               <entry>
 964                 <para>Provides brief help on various
 965                 <literal>lfs</literal> arguments.</para>
 966               </entry>
 967             </row>
 968             <row>
 969               <entry nameend="c2" namest="c1">
 970                 <para>
 971                   <literal>exit/quit</literal>
 972                 </para>
 973               </entry>
 974               <entry>
 975                 <para>Quits the interactive
 976                 <literal>lfs</literal> session.</para>
 977               </entry>
 978             </row>
 979           </tbody>
 980         </tgroup>
 981       </informaltable>
 982     </section>
 983     <section remap="h5" xml:id="dbdoclet.50438206_11903">
 984       <title>Examples</title>
 985       <para>Creates a file striped on two OSTs with 128 KB on each
 986       stripe.</para>
 987       <screen>
 988 $ lfs setstripe -s 128k -c 2 /mnt/lustre/file1
 989 </screen>
 990       <para>Deletes a default stripe pattern on a given directory. New files
 991       use the default striping pattern.</para>
 992       <screen>
 993 $ lfs setstripe -d /mnt/lustre/dir
 994 </screen>
 995       <para>Lists the detailed object allocation of a given file.</para>
 996       <screen>
 997 $ lfs getstripe -v /mnt/lustre/file1
 998 </screen>
 999       <para>List all the mounted Lustre file systems and corresponding Lustre
1000       instances.</para>
1001       <screen>
1002 $ lfs getname
1003 </screen>
1004       <para>Efficiently lists all files in a given directory and its
1005       subdirectories.</para>
1006       <screen>
1007 $ lfs find /mnt/lustre
1008 </screen>
1009       <para>Recursively lists all regular files in a given directory more than
1010       30 days old.</para>
1011       <screen>
1012 $ lfs find /mnt/lustre -mtime +30 -type f -print
1013 </screen>
1014       <para>Recursively lists all files in a given directory that have objects
1015       on OST2-UUID. The lfs check servers command checks the status of all
1016       servers (MDT and OSTs).</para>
1017       <screen>
1018 $ lfs find --obd OST2-UUID /mnt/lustre/
1019 </screen>
1020       <para>Lists all OSTs in the file system.</para>
1021       <screen>
1022 $ lfs osts
1023 </screen>
1024       <para>Lists space usage per OST and MDT in human-readable format.</para>
1025       <screen>
1026 $ lfs df -h
1027 </screen>
1028       <para>Lists inode usage per OST and MDT.</para>
1029       <screen>
1030 $ lfs df -i
1031 </screen>
1032       <para>List space or inode usage for a specific OST pool.</para>
1033       <screen>
1034 $ lfs df --pool
1035 <replaceable>filesystem</replaceable>[.
1036 <replaceable>pool</replaceable>] |
1037 <replaceable>pathname</replaceable>
1038 </screen>
1039       <para>List quotas of user 'bob'.</para>
1040       <screen>
1041 $ lfs quota -u bob /mnt/lustre
1042 </screen>
1043       <para>List quotas of project ID '1'.</para>
1044       <screen>
1045 $ lfs quota -p 1 /mnt/lustre
1046 </screen>
1047       <para>Show grace times for user quotas on
1048       <literal>/mnt/lustre</literal>.</para>
1049       <screen>
1050 $ lfs quota -t -u /mnt/lustre
1051 </screen>
1052       <para>Changes file owner and group.</para>
1053       <screen>
1054 $ lfs quotachown -i /mnt/lustre
1055 </screen>
1056       <para>Checks quotas for user and group. Turns on quotas after making the
1057       check.</para>
1058       <screen>
1059 $ lfs quotacheck -ug /mnt/lustre
1060 </screen>
1061       <para>Turns on quotas of user and group.</para>
1062       <screen>
1063 $ lfs quotaon -ug /mnt/lustre
1064 </screen>
1065       <para>Turns off quotas of user and group.</para>
1066       <screen>
1067 $ lfs quotaoff -ug /mnt/lustre
1068 </screen>
1069       <para>Sets quotas of user 'bob', with a 1 GB block quota hardlimit and a
1070       2 GB block quota softlimit.</para>
1071       <screen>
1072 $ lfs setquota -u bob --block-softlimit 2000000 --block-hardlimit 1000000
1073 /mnt/lustre
1074 </screen>
1075       <para>Sets grace times for user quotas: 1000 seconds for block quotas, 1
1076       week and 4 days for inode quotas.</para>
1077       <screen>
1078 $ lfs setquota -t -u --block-grace 1000 --inode-grace 1w4d /mnt/lustre
1079 </screen>
1080       <para>Checks the status of all servers (MDT, OST)</para>
1081       <screen>
1082 $ lfs check servers
1083 </screen>
1084       <para>Creates a file striped on two OSTs from the pool
1085       <literal>my_pool</literal></para>
1086       <screen>
1087 $ lfs setstripe --pool my_pool -c 2 /mnt/lustre/file
1088 </screen>
1089       <para>Lists the pools defined for the mounted Lustre file system
1090       <literal>/mnt/lustre</literal></para>
1091       <screen>
1092 $ lfs pool_list /mnt/lustre/
1093 </screen>
1094       <para>Lists the OSTs which are members of the pool
1095       <literal>my_pool</literal> in file system
1096       <literal>my_fs</literal></para>
1097       <screen>
1098 $ lfs pool_list my_fs.my_pool
1099 </screen>
1100       <para>Finds all directories/files associated with
1101       <literal>poolA</literal>.</para>
1102       <screen>
1103 $ lfs find /mnt/lustre --pool poolA
1104 </screen>
1105       <para>Finds all directories/files not associated with a pool.</para>
1106       <screen>
1107 $ lfs find /mnt//lustre --pool ""
1108 </screen>
1109       <para>Finds all directories/files associated with pool.</para>
1110       <screen>
1111 $ lfs find /mnt/lustre ! --pool ""
1112 </screen>
1113       <para>Associates a directory with the pool
1114       <literal>my_pool</literal>, so all new files and directories are created
1115       in the pool.</para>
1116       <screen>
1117 $ lfs setstripe --pool my_pool /mnt/lustre/dir
1118 </screen>
1119     </section>
1120     <section remap="h5">
1121       <title>See Also</title>
1122       <para>
1123         <xref linkend="dbdoclet.50438219_38274" />
1124       </para>
1125     </section>
1126   </section>
1127   <section xml:id="dbdoclet.lfs_migrate">
1128     <title>
1129       <indexterm>
1130         <primary>lfs_migrate</primary>
1131       </indexterm>
1132       <literal>lfs_migrate</literal>
1133     </title>
1134     <para>The
1135     <literal>lfs_migrate</literal> utility is a simple to migrate file
1136     <emphasis>data</emphasis> between OSTs.</para>
1137     <section remap="h5">
1138       <title>Synopsis</title>
1139       <screen>
1140 lfs_migrate [<replaceable>lfs_setstripe_options</replaceable>]
1141         [-h] [-n] [-q] [-R] [-s] [-y] [-0] [file|directory ...]
1142 </screen>
1143     </section>
1144     <section remap="h5">
1145       <title>Description</title>
1146       <para>The
1147       <literal>lfs_migrate</literal> utility is a tool to assist migration
1148       of file data between Lustre OSTs. The utility copies each specified
1149       file to a temporary file using supplied <literal>lfs setstripe</literal>
1150       options, if any, optionally verifies the file contents have not changed,
1151       and then swaps the layout (OST objects) from the temporary file and the
1152       original file (for Lustre 2.5 and later), or renames the temporary file
1153       to the original filename. This allows the user/administrator to balance
1154       space usage between OSTs, or move files off OSTs that are starting to show
1155       hardware problems (though are still functional) or will be removed.</para>
1156       <warning>
1157         <para>For versions of Lustre before 2.5,
1158         <literal>lfs_migrate</literal> was not integrated with the MDS at all.
1159         That made it UNSAFE for use on files that were being modified by other
1160         applications, since the file was migrated through a copy and rename of
1161         the file.  With Lustre 2.5 and later, the new file layout is swapped
1162         with the existing file layout, which ensures that the user-visible
1163         inode number is kept, and open file handles and locks on the file are
1164         kept.</para>
1165       </warning>
1166       <para>Files to be migrated can be specified as command-line arguments. If
1167       a directory is specified on the command-line then all files within the
1168       directory are migrated. If no files are specified on the command-line,
1169       then a list of files is read from the standard input, making
1170       <literal>lfs_migrate</literal> suitable for use with
1171       <literal>lfs find</literal> to locate files on specific OSTs and/or
1172       matching other file attributes, and other tools that generate a list
1173       of files on standard output.</para>
1174       <para>Unless otherwise specified through command-line options, the
1175       file allocation policies on the MDS dictate where the new files
1176       are placed, taking into account whether specific OSTs have been
1177       disabled on the MDS via <literal>lctl</literal> (preventing new
1178       files from being allocated there), whether some OSTs are overly full
1179       (reducing the number of files placed on those OSTs), or if there is
1180       a specific default file striping for the parent directory (potentially
1181       changing the stripe count, stripe size, OST pool, or OST index of a
1182       new file).</para>
1183       <note>
1184         <para>The
1185         <literal>lfs_migrate</literal> utility can also be used in some cases to
1186         reduce file
1187         <indexterm>
1188           <primary>fragmentation</primary>
1189         </indexterm>fragmentation. File fragmentation will typically reduce
1190         Lustre file system performance. File fragmentation may be observed on
1191         an aged file system and will commonly occur if the file was written by
1192         many threads. Provided there is sufficient free space (or if it was
1193         written when the file system was nearly full) that is less fragmented
1194         than the file being copied, re-writing a file with
1195         <literal>lfs_migrate</literal> will result in a migrated file with
1196         reduced fragmentation. The tool
1197         <literal>filefrag</literal> can be used to report file fragmentation.
1198         See
1199         <xref linkend="dbdoclet.50438206_75125" /></para>
1200       </note>
1201       <note>
1202         <para>As long as a file has extent lengths of tens of megabytes (
1203         <replaceable>read_bandwidth * seek_time</replaceable>) or more, the
1204         read performance for the file will not be significantly impacted by
1205         fragmentation, since the read pipeline can be filled by large reads
1206         from disk even with an occasional disk seek.</para>
1207       </note>
1208     </section>
1209     <section remap="h5">
1210       <title>Options</title>
1211       <para>Options supporting
1212       <literal>lfs_migrate</literal> are described below.</para>
1213       <informaltable frame="all">
1214         <tgroup cols="2">
1215           <colspec colname="c1" colwidth="50*" />
1216           <colspec colname="c2" colwidth="50*" />
1217           <thead>
1218             <row>
1219               <entry>
1220                 <para>
1221                   <emphasis role="bold">Option</emphasis>
1222                 </para>
1223               </entry>
1224               <entry>
1225                 <para>
1226                   <emphasis role="bold">Description</emphasis>
1227                 </para>
1228               </entry>
1229             </row>
1230           </thead>
1231           <tbody>
1232             <row>
1233               <entry>
1234                 <para>
1235                   <literal>-c
1236                   <replaceable>stripecount</replaceable></literal>
1237                 </para>
1238               </entry>
1239               <entry>
1240                 <para>Restripe file using the specified stripe count. This
1241                 option may not be specified at the same time as the
1242                 <literal>-R</literal> option.</para>
1243               </entry>
1244             </row>
1245             <row>
1246               <entry>
1247                 <para>
1248                   <literal>-h</literal>
1249                 </para>
1250               </entry>
1251               <entry>
1252                 <para>Display help information.</para>
1253               </entry>
1254             </row>
1255             <row>
1256               <entry>
1257                 <literal>-l</literal>
1258               </entry>
1259               <entry>
1260                 <para>Migrate files with hard links (skips, by default). Files
1261                 with multiple hard links are split into multiple separate files
1262                 by
1263                 <literal>lfs_migrate</literal>, so they are skipped, by
1264                 default, to avoid breaking the hard links.</para>
1265               </entry>
1266             </row>
1267             <row>
1268               <entry>
1269                 <literal>-n</literal>
1270               </entry>
1271               <entry>
1272                 <para>Only print the names of files to be migrated.</para>
1273               </entry>
1274             </row>
1275             <row>
1276               <entry>
1277                 <para>
1278                   <literal>-q</literal>
1279                 </para>
1280               </entry>
1281               <entry>
1282                 <para>Run quietly (does not print filenames or status).</para>
1283               </entry>
1284             </row>
1285             <row>
1286               <entry>
1287                 <literal>-R</literal>
1288               </entry>
1289               <entry>Restripe file using default directory striping instead of
1290               keeping striping. This option may not be specified at the same
1291               time as the
1292               <literal>-c</literal> option.</entry>
1293             </row>
1294             <row>
1295               <entry>
1296                 <literal>-s</literal>
1297               </entry>
1298               <entry>Skip file data comparison after migrate. Default is to
1299               compare migrated file against original to verify
1300               correctness.</entry>
1301             </row>
1302             <row>
1303               <entry>
1304                 <para>
1305                   <literal>-y</literal>
1306                 </para>
1307               </entry>
1308               <entry>
1309                 <para>Answer '
1310                 <literal>y</literal>' to usage warning without prompting (for
1311                 scripts, use with caution).</para>
1312               </entry>
1313             </row>
1314             <row>
1315               <entry>
1316                 <literal>-0</literal>
1317               </entry>
1318               <entry>Expect NUL-terminated filenames on standard input, as
1319               generated by <literal>lfs find -print0</literal> or
1320               <literal>find -print0</literal>.  This allows filenames with
1321               embedded newlines to be handled correctly.
1322               </entry>
1323             </row>
1324           </tbody>
1325         </tgroup>
1326       </informaltable>
1327     </section>
1328     <section remap="h5">
1329       <title>Examples</title>
1330       <para>Rebalance all files in
1331       <literal>/mnt/lustre/dir</literal>:</para>
1332       <screen>
1333 $ lfs_migrate /mnt/lustre/dir
1334 </screen>
1335       <para>Migrate files in /test filesystem on OST0004 larger than 4 GB in
1336       size and older than a day old:</para>
1337       <screen>
1338 $ lfs find /test -obd test-OST0004 -size +4G -mtime +1 | lfs_migrate -y
1339 </screen>
1340     </section>
1341     <section remap="h5">
1342       <title>See Also</title>
1343       <para>
1344         <xref linkend="dbdoclet.50438206_94597" />
1345       </para>
1346     </section>
1347   </section>
1348   <section xml:id="dbdoclet.50438206_75125">
1349     <title>
1350       <indexterm>
1351         <primary>filefrag</primary>
1352       </indexterm>
1353       <literal>filefrag</literal>
1354     </title>
1355     <para>The
1356     <literal>e2fsprogs</literal> package contains the
1357     <literal>filefrag</literal> tool which reports the extent of file
1358     fragmentation.</para>
1359     <section remap="h5">
1360       <title>Synopsis</title>
1361       <screen>
1362 filefrag [ -belsv ] [ files...  ]
1363 </screen>
1364     </section>
1365     <section remap="h5">
1366       <title>Description</title>
1367       <para>The
1368       <literal>filefrag</literal> utility reports the extent of fragmentation in
1369       a given file. The
1370       <literal>filefrag</literal> utility obtains the extent information from
1371       Lustre files using the
1372       <literal>FIEMAP ioctl</literal>, which is efficient and fast, even for
1373       very large files.</para>
1374       <para>In default mode
1375       <footnote>
1376         <para>The default mode is faster than the verbose/extent mode since it
1377         only counts the number of extents.</para>
1378       </footnote>,
1379       <literal>filefrag</literal> prints the number of physically discontiguous
1380       extents in the file. In extent or verbose mode, each extent is printed
1381       with details such as the blocks allocated on each OST. For a Lustre file
1382       system, the extents are printed in device offset order (i.e. all of the
1383       extents for one OST first, then the next OST, etc.), not file logical
1384       offset order. If the file logical offset order was used, the Lustre
1385       striping would make the output very verbose and difficult to see if there
1386       was file fragmentation or not.</para>
1387       <note>
1388         <para>Note that as long as a file has extent lengths of tens of
1389         megabytes or more (i.e.
1390         <replaceable>read_bandwidth * seek_time &gt;
1391         extent_length</replaceable>), the read performance for the file will
1392         not be significantly impacted by fragmentation, since file readahead
1393         can fully utilize the disk disk bandwidth even with occasional
1394         seeks.</para>
1395       </note>
1396       <para>In default mode
1397       <footnote>
1398         <para>The default mode is faster than the verbose/extent mode.</para>
1399       </footnote>,
1400       <literal>filefrag</literal> returns the number of physically discontiguous
1401       extents in the file. In extent or verbose mode, each extent is printed
1402       with details. For a Lustre file system, the extents are printed in device
1403       offset order, not logical offset order.</para>
1404     </section>
1405     <section remap="h5">
1406       <title>Options</title>
1407       <para>The options and descriptions for the
1408       <literal>filefrag</literal> utility are listed below.</para>
1409       <informaltable frame="all">
1410         <tgroup cols="2">
1411           <colspec colname="c1" colwidth="50*" />
1412           <colspec colname="c2" colwidth="50*" />
1413           <thead>
1414             <row>
1415               <entry>
1416                 <para>
1417                   <emphasis role="bold">Option</emphasis>
1418                 </para>
1419               </entry>
1420               <entry>
1421                 <para>
1422                   <emphasis role="bold">Description</emphasis>
1423                 </para>
1424               </entry>
1425             </row>
1426           </thead>
1427           <tbody>
1428             <row>
1429               <entry>
1430                 <para>
1431                   <literal>-b</literal>
1432                 </para>
1433               </entry>
1434               <entry>
1435                 <para>Uses the 1024-byte blocksize for the output. By default,
1436                 this blocksize is used by the Lustre file system, since OSTs
1437                 may use different block sizes.</para>
1438               </entry>
1439             </row>
1440             <row>
1441               <entry>
1442                 <para>
1443                   <literal>-e</literal>
1444                 </para>
1445               </entry>
1446               <entry>
1447                 <para>Uses the extent mode when printing the output. This is
1448                 the default for Lustre files in verbose mode.</para>
1449               </entry>
1450             </row>
1451             <row>
1452               <entry>
1453                 <para>
1454                   <literal>-l</literal>
1455                 </para>
1456               </entry>
1457               <entry>
1458                 <para>Displays extents in LUN offset order. This is the only
1459                 available mode for Lustre.</para>
1460               </entry>
1461             </row>
1462             <row>
1463               <entry>
1464                 <para>
1465                   <literal>-s</literal>
1466                 </para>
1467               </entry>
1468               <entry>
1469                 <para>Synchronizes any unwritten file data to disk before
1470                 requesting the mapping.</para>
1471               </entry>
1472             </row>
1473             <row>
1474               <entry>
1475                 <para>
1476                   <literal>-v</literal>
1477                 </para>
1478               </entry>
1479               <entry>
1480                 <para>Prints the file's layout in verbose mode when checking
1481                 file fragmentation, including the logical to physical mapping
1482                 for each extent in the file and the OST index.</para>
1483               </entry>
1484             </row>
1485           </tbody>
1486         </tgroup>
1487       </informaltable>
1488     </section>
1489     <section remap="h5">
1490       <title>Examples</title>
1491       <para>Lists default output.</para>
1492       <screen>
1493 $ filefrag /mnt/lustre/foo
1494 /mnt/lustre/foo: 13 extents found
1495 </screen>
1496       <para>Lists verbose output in extent format.</para>
1497       <screen>
1498 $ filefrag -v /mnt/lustre/foo
1499 Filesystem type is: bd00bd0
1500 File size of /mnt/lustre/foo is 1468297786 (1433888 blocks of 1024 bytes)
1501  ext:     device_logical:        physical_offset: length:  dev: flags:
1502    0:        0..  122879: 2804679680..2804802559: 122880: 0002: network
1503    1:   122880..  245759: 2804817920..2804940799: 122880: 0002: network
1504    2:   245760..  278527: 2804948992..2804981759:  32768: 0002: network
1505    3:   278528..  360447: 2804982784..2805064703:  81920: 0002: network
1506    4:   360448..  483327: 2805080064..2805202943: 122880: 0002: network
1507    5:   483328..  606207: 2805211136..2805334015: 122880: 0002: network
1508    6:   606208..  729087: 2805342208..2805465087: 122880: 0002: network
1509    7:   729088..  851967: 2805473280..2805596159: 122880: 0002: network
1510    8:   851968..  974847: 2805604352..2805727231: 122880: 0002: network
1511    9:   974848.. 1097727: 2805735424..2805858303: 122880: 0002: network
1512   10:  1097728.. 1220607: 2805866496..2805989375: 122880: 0002: network
1513   11:  1220608.. 1343487: 2805997568..2806120447: 122880: 0002: network
1514   12:  1343488.. 1433599: 2806128640..2806218751:  90112: 0002: network
1515 /mnt/lustre/foo: 13 extents found
1516 </screen>
1517     </section>
1518   </section>
1519   <section xml:id="dbdoclet.50438206_86244">
1520     <title>
1521       <indexterm>
1522         <primary>mount</primary>
1523       </indexterm>
1524       <literal>mount</literal>
1525     </title>
1526     <para>The standard
1527     <literal>mount(8)</literal> Linux command is used to mount a Lustre file
1528     system. When mounting a Lustre file system, mount(8) executes the
1529     <literal>/sbin/mount.lustre</literal> command to complete the mount. The
1530     mount command supports these options specific to a Lustre file
1531     system:</para>
1532     <informaltable frame="all">
1533       <tgroup cols="2">
1534         <colspec colname="c1" colwidth="50*" />
1535         <colspec colname="c2" colwidth="50*" />
1536         <thead>
1537           <row>
1538             <entry>
1539               <para>
1540                 <emphasis role="bold">Server options</emphasis>
1541               </para>
1542             </entry>
1543             <entry>
1544               <para>
1545                 <emphasis role="bold">Description</emphasis>
1546               </para>
1547             </entry>
1548           </row>
1549         </thead>
1550         <tbody>
1551           <row>
1552             <entry>
1553               <para>
1554                 <literal>abort_recov</literal>
1555               </para>
1556             </entry>
1557             <entry>
1558               <para>Aborts recovery when starting a target</para>
1559             </entry>
1560           </row>
1561           <row>
1562             <entry>
1563               <para>
1564                 <literal>nosvc</literal>
1565               </para>
1566             </entry>
1567             <entry>
1568               <para>Starts only MGS/MGC servers</para>
1569             </entry>
1570           </row>
1571           <row>
1572             <entry>
1573               <para>
1574                 <literal>nomgs</literal>
1575               </para>
1576             </entry>
1577             <entry>
1578               <para>Start a MDT with a co-located MGS without starting the
1579               MGS</para>
1580             </entry>
1581           </row>
1582           <row>
1583             <entry>
1584               <para>
1585                 <literal>exclude</literal>
1586               </para>
1587             </entry>
1588             <entry>
1589               <para>Starts with a dead OST</para>
1590             </entry>
1591           </row>
1592           <row>
1593             <entry>
1594               <para>
1595                 <literal>md_stripe_cache_size</literal>
1596               </para>
1597             </entry>
1598             <entry>
1599               <para>Sets the stripe cache size for server side disk with a
1600               striped raid configuration</para>
1601             </entry>
1602           </row>
1603         </tbody>
1604       </tgroup>
1605     </informaltable>
1606     <informaltable frame="all">
1607       <tgroup cols="2">
1608         <colspec colname="c1" colwidth="50*" />
1609         <colspec colname="c2" colwidth="50*" />
1610         <thead>
1611           <row>
1612             <entry>
1613               <para>
1614                 <emphasis role="bold">Client options</emphasis>
1615               </para>
1616             </entry>
1617             <entry>
1618               <para>
1619                 <emphasis role="bold">Description</emphasis>
1620               </para>
1621             </entry>
1622           </row>
1623         </thead>
1624         <tbody>
1625           <row>
1626             <entry>
1627               <para>
1628                 <literal>flock/noflock/localflock</literal>
1629               </para>
1630             </entry>
1631             <entry>
1632               <para>Enables/disables global flock or local flock support</para>
1633             </entry>
1634           </row>
1635           <row>
1636             <entry>
1637               <para>
1638                 <literal>user_xattr/nouser_xattr</literal>
1639               </para>
1640             </entry>
1641             <entry>
1642               <para>Enables/disables user-extended attributes</para>
1643             </entry>
1644           </row>
1645           <row>
1646             <entry>
1647               <para>
1648                 <literal>user_fid2path/nouser_fid2path</literal>
1649               </para>
1650             </entry>
1651             <entry>
1652               <para>Enables/disables FID to path translation by
1653               regular users</para>
1654             </entry>
1655           </row>
1656           <row>
1657             <entry>
1658               <para>
1659                 <literal>retry=</literal>
1660               </para>
1661             </entry>
1662             <entry>
1663               <para>Number of times a client will retry to mount the file
1664               system</para>
1665             </entry>
1666           </row>
1667         </tbody>
1668       </tgroup>
1669     </informaltable>
1670   </section>
1671   <section xml:id="dbdoclet.50438206_56217">
1672     <title>Handling Timeouts</title>
1673     <para>Timeouts are the most common cause of hung applications. After a
1674     timeout involving an MDS or failover OST, applications attempting to access
1675     the disconnected resource wait until the connection gets
1676     established.</para>
1677     <para>When a client performs any remote operation, it gives the server a
1678     reasonable amount of time to respond. If a server does not reply either due
1679     to a down network, hung server, or any other reason, a timeout occurs which
1680     requires a recovery.</para>
1681     <para>If a timeout occurs, a message (similar to this one), appears on the
1682     console of the client, and in
1683     <literal>/var/log/messages</literal>:</para>
1684     <screen>
1685 LustreError: 26597:(client.c:810:ptlrpc_expire_one_request()) @@@ timeout
1686
1687 req@a2d45200 x5886/t0 o38-&gt;mds_svc_UUID@NID_mds_UUID:12 lens 168/64 ref 1 fl
1688
1689 RPC:/0/0 rc 0
1690 </screen>
1691   </section>
1692 </chapter>