--- /dev/null
+.\" -*- nroff -*-
+.\" Copyright 2008 by Sun Microsystems. All Rights Reserved.
+.\" This file may be copied under the terms of the GNU Public License, v2.
+.\"
+.TH llbackup 8 "2008 Mar 15" Lustre "System management commands"
+.SH NAME
+llbackup \- backup a list of files, maybe running on multiple nodes
+.SH SYNOPSIS
+.B llbackup
+.RB [ -chjvxz "] [" -C
+.IR directory ]
+.RB [ -e
+.IR rsh ]
+.RB [ -i
+.IR inputlist ]
+.RB [ -l
+.IR logdir ]
+.RB [ -n
+.IR nodes ]
+.RB [ -s
+.IR splitmb ]
+.RB [ -T
+.IR tar ]
+.BI -f outputfilebase
+.SH DESCRIPTION
+.B llbackup
+takes a list of files to backup or restore, either from standard input, or
+from a list of files supplied as a parameter and produces one or more archive
+files containing the files.
+.B llbackup
+uses the
+.BR tar (1)
+or
+.BR htar (1)
+programs to produce archive files, and has many of the same options (though
+not identical in some cases). The reason for using llbackup instead of those
+programs directly is that llbackup can run in parallel on multiple
+nodes to do high-speed backups on clustered or distributed filesystems and
+will split the work among multiple client nodes to increase performance.
+The archive files produced are identical to normal tar files (having been
+created by the local tar command) and can be extracted or listed by tar
+directly.
+.br
+The clients will pause and print status messages if they think there is not
+enough free space in the output directory to avoid running out of space.
+Backup tarfiles should be moved to offline storage or otherwise purged to
+allow the backups to continue. If the client is doing a restore it will
+similarly pause and print status messages if the tarfile it was asked to
+restore is not available on that node.
+.sh OPTIONS
+.TP
+.B -c
+create archive. This is the default operation if no other is given.
+.TP
+.BI -C directory
+change the backup command to run in
+.I directory
+instead of the current working directory so filenames given in the input
+file are backed up or restored relative to
+.IR directory .
+Note that this affects all pathname components used during backup and restore
+so the
+.I inputlist
+and
+.I outputbase
+should be specified by absolute pathname if they are not also in
+.IR directory .
+.TP
+.BI -e rsh
+specify the passwordless remote shell command (default
+.BR ssh (1)).
+.TP
+.BI -f outputbase
+specify base output filename for backup tar archives, to which a suffix will
+be appended to ensure that multiple clients doing backup into the same
+directory do not have conflicting filenames. For restore or list operations
+this is a file containing a list of tarfiles, one per line, to restore or
+list the table of contents of. The
+.I outputbase
+file can be a tape or disk device, but must be the same device on each client
+running the backup, in which case only a single process can run on each client.
+.TP
+.B -h
+print this help message and exit. Use
+.B -x
+.B -h
+or
+.B -t
+.B -h
+to get the help options for restore or list operations.
+.TP
+.BI -i inputlist
+list of files to backup when creating an archive (default stdin). The input
+file list is just a list of pathnames, one file per line, as generated by
+.BR find (8),
+.BR "lfs find" (8),
+or
+.BR e2scan (8)
+for example. For restore this option is currently unused.
+.TP
+.B -j
+use
+.BR bzip2 (1)
+compression on input or output tar file(s). This option is not
+currently supported by the underlying
+.BR htar (8)
+implementation.
+.TP
+.BI -l logdir
+directory for output logs.
+.TP
+.BI -n nodes
+comma-separated list of client nodes to run backups. It is possible to
+specify the same client node multiple times in order to have multiple
+instances of the backup or restore running in parallel on that node.
+This is useful to maximize the bandwidth of the backup or restore process
+and avoid client nodes underutilizing their bandwidth while generating
+file lists or compressing files.
+.TP
+.BI -s splitmb
+target size for backup chunks in megabytes (default 8192MiB). Increasing this
+size can improve performance and compression ratios, but may cause
+underutilization of clients if the files are not evenly distributed.
+This option has no meaning for restore or list operations.
+.TP
+.BI -S splitcount
+number of files sent to each client before sending files to the next client
+(default 200). Increasing the
+.I splitcount
+keeps more related files together in individual tar files (meaning fewer
+archives need to be processed when restoring files for a particular
+subdirectory), but can lead to performance imbalance if files vary greatly
+in size and one client has to back up many of them due to proximity of
+filenames in the input list, while other clients back up smaller files.
+Decreasing the
+.I splitcount
+means a more uniform distribution of files and usage among clients, but
+means nearly every archive will have to be extracted to get only a subset
+of files needed.
+This option has no meaning for restore or list operations.
+.TP
+.B -t
+list table of contents of the list of tarfiles given by
+.BR -f .
+.TP
+.BI -T tar
+specify the backup command (default tar). Optionally the
+.BI htar (8)
+command can be used to back up directly to an HPSS archive, if available.
+.TP
+.B -v
+be verbose - list all files being processed. By default, individual files
+being backed up or restored are only reported in the log files because they
+would all be intermixed coming from multiple clients in parallel and the
+overall progress would be hard to determine.
+.TP
+.B -V
+print version number and exit.
+.TP
+.B -x
+extract tarfiles from the list of tarfiles given by
+.B -f
+instead of backing them up.
+.TP
+.B -z
+use gzip compression on input or output tar file(s). This option is not
+currently supported by the underlying
+.BR htar (8)
+implementation.
+.SH EXAMPLES
+.TP
+.B lfs find /home -mtime -7 | llbackup -c -n c1,c2 -f /bkup/bk2008-03-15
+Create a backup of the
+.B /home
+filesystem finding files modified in the last 7 days, compress the output
+using
+.B gzip
+and run on client nodes
+.B c1
+nodes, putting the output tar files into the
+.B /bkup
+directory using filenames starting with bk2008-03-15:
+.TP
+.B find /bkup -name bk2007-11-28* | llbackup -x -n c1,c1,c2,c2 -C /tmp -f-
+Restore
+.B gzip
+compressed files from the
+.B bk2007-11-28
+backup from the
+.B /bkup
+directory, using two restore processes on each of the client nodes
+.B c1
+and
+.BR c2 ,
+reading the list of tar files to restore from standard input and restoring
+into the
+.B /tmp
+directory:
+.SH BUGS
+It is currently not possible to extract only a subset of files from the
+tarfiles. If that is necessary, then tar should be run directly on the
+individual tar files after checking in the backup logs which tarfiles
+have the relevant files.
+.SH SEE ALSO
+.BR lustre (7),
+.BR tar (8),
+.BR htar (8),
+.BR ssh (1),
+.BR rsh (1),
+.BR find (1),
+.BR lfs "(1) " find ,
+.BR e2scan (8).
git://git.whamcloud.com / fs / lustre-release.git / blobdiff