.B lfs setdirstripe [\fR-cdDHioTx\fR] \fIDIR\fR...
.br
.SH DESCRIPTION
-Create a striped directory with specified striping pattern. This lfs utility
-is similar to
-.BR lfs setstripe
-, but is used to create striped directory.
+Create a striped directory with specified striping pattern. This
+.B lfs
+sub-command is similar to
+.BR "lfs setstripe" ,
+but is used to create a striped directory or set the default layout for
+subdirectories.
Can also be used to create directory with a foreign (free format) striping pattern (see
.BR --foreign
and
as the master/starting MDT for the directory. If multiple
.I MDT_INDEX
values are given, then the stripes will be allocated on the specified
-MDT indices. If index -1 (default) is used, it will randomly pick
-.I COUNT
-less full MDTs.
+MDT indices. If index -1 (default) is used, it will prefer to select
+.B COUNT
+MDTs proportional to the free space and inodes on each.
.TP
.BR \-H ", " \-\-mdt-hash =\fIHASH_TYPE\fR
Use
for the striped directory.
.RS 1.2i
.TP
+.B crush
+CRUSH hash algorithm. This is a consistent hash
+algorithm, so minimum sub files need to relocate
+during directory restripe.
+.TP
.B fnv_1a_64
Fowler-Noll-Vo (FNV-1a) hash algorithm. This provides
reasonably uniform, but not cryptographically strong,
created sub-directories will also inherit the specified default
striping pattern. Only default stripe count is supported for now.
-Note that striping all directories across all MDTs by default is not
+Note that striping all directories across all MDTs by default is
+.B not
recommended at this time, as the clients will have to do more RPCs to
create and access each directory, hurting performance rather than
-improving it. Default striped directories are preferred for cases
+improving it. Default striped directories are preferred for parent
+directories
where large subdirectories will be created (e.g. file-per-process
job output directories).
.TP
option) striping. Where
.BR type
specifies a known foreign type (like
-.BR none
-,
-.BR daos
-, ...) or a 32-bit numeric type.
+.BR none ,
+.BR daos )
+or a 32-bit numeric type.
.TP
.BR \-\-flags =\fI<hex>\fR
-Specify a bitmask of flags.
+Specify a numeric bitmask of type-specific layout flags for the foreign layout.
.TP
.BR \-x ", " \-\-xattr =\fISTRING\fR
Specify a string to be used as a foreign (free format) striping.
.PP
The
.B lfs setdirstripe
-command is only executable by root unless
+command is only usable by root unless the
.B "mdt.*.enable_remote_dir_gid"
is set on the MDS via
.B lctl set_param
-to be either a non-zero GID to limit it to a single group
-(e.g. "operator" or "admin"), or "-1" to allow any group
-to create remote directories.
+to be either a non-zero numeric GID to limit it to a single group (e.g. the
+.BR "operator " or " admin"
+GID), or
+.B "-1"
+to allow any user/group to create remote directories. By default, it is
+.B "0"
+to limit remote/striped directories to only the root user.
-The root of the file system is on MDT0000, and directories and files inherit the
-MDT of their parent directory unless a different MDT is specified with this
-command.
+The root directory of the file system is on MDT0000, and directories and
+files inherit the MDT of their parent directory unless a different MDT is
+specified with this command.
By default, only directories on MDT0000 can contain directories that are not on
-the same MDT. However, if "mdt.*.enable_remote_dir" is set non-zero on an MDT
+the same MDT. However, if
+.B "mdt.*.enable_remote_dir"
+is set non-zero on an MDT (the default)
then it will allow creating remote directories that have parents other than
MDT0000. This is restricted to avoid creating directory trees that have
intermediate path components on a series different MDTs and become unavailable
git://git.whamcloud.com / fs / lustre-release.git / blobdiff