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.TH rsync-backup 8 "7 October 2012" rsync-backup
+.SH NAME
+rsync-backup \- back up files using rsync
.SH SYNOPSIS
.B rsync-backup
-.RB [ \-v ]
+.RB [ \-nv ]
.RB [ \-c
.IR config-file ]
.SH DESCRIPTION
.B \-V
output).
.TP
+.B \-n
+Don't actually take a backup, or write proper logs: instead, write a
+description of what would be done to standard error.
+.TP
.B \-v
Produce verbose progress information on standard output while the backup
is running. This keeps one amused while running a backup
The configuration file is simply a Bash shell fragment: configuration
commands are shell functions.
.TP
+.BI "addhook " hook " " command
+Arrange that the named
+.I hook
+runs the given
+.IR command .
+See
+.B runhook
+for more details.
+.TP
.BI "backup " "fs\fR[:\fIfsarg\fR] ..."
Back up the named filesystems. The corresponding
.IR fsarg s
may be required by the snapshot type.
.TP
+.BI "defhook " hook
+Define a new hook named
+.IR hook .
+See
+.B addhook
+and
+.B runhook
+for more information.
+.TP
.BI "host " host
Future
.B backup
in this case.
This command clears the
.B like
-list.
+list, the remote
+.B user
+name, and resets the retention policy to its default (i.e., the to
+policy defined prior to the first
+.B host
+command).
.TP
.BI "like " "host\fR ..."
Declare that subsequent filesystems are `similar' to like-named
Expiry considers each existing dump against the policy lines in order:
the last applicable line determines the dump's fate \(en so you should
probably write the lines in decreasing order of duration.
+.RS
+.PP
+Groups of
+.B retain
+commands between
+.B host
+and/or
+.B backup
+commands collectively define a retention policy. Once a policy is
+defined, subsequent
+.B backup
+operations use the policy. The first
+.B retain
+command after a
+.B host
+or
+.B backup
+command clears the policy and starts defining a new one. The policy
+defined before the first
+.B host
+is the
+.I default
+policy: at the start of each
+.B host
+stanza, the policy is reset to the default.
+.RE
+.TP
+.BI "retry " count
+The
+.B live
+snapshot type (see below) doesn't prevent a filesystem from being
+modified while it's being backed up. If this happens, the
+.B fshash
+pass will detect the difference and fail. If the filesystem in question
+is relatively quiescent, then maybe retrying the backup will result in a
+successful consistent copy. Following this command, a backup which
+results in an
+.B fshash
+mismatch will be retried up to
+.I count
+times before being declared a failure. The default is to retry once,
+clearing mismatching files from the
+.BR fshash (1)
+caches before the second attempt.
+.TP
+.BI "runhook " hook " " args\fR...
+Invoke the named
+.IR hook .
+The individual commands on the hook are run, in order, as
+.RS
+.IP
+.I command
+.IR args ...
+.PP
+If any command fails (returns nonzero) then no other hooks are run and
+.B runhook
+fails with the same exit code.
+.RE
.TP
.BI "snap " type " " \fR[\fIargs\fR...]
Use the snapshot
.I type
for subsequent backups. Some snapshot types require additional
-arguments, which may be supplied here.
+arguments, which may be supplied here. This command clears the
+.B retry
+counter.
+.TP
+.BI "user " name
+Specify the user name on the remote host. Without this, calls to
+.BR ssh (1)
+and
+.BR rsync (1)
+won't specify any user name, so the default (probably from the
+.BR ssh_config (5)
+file) will apply.
.SS Configuration variables
The following shell variables may be overridden by the configuration
file.
.TP
+.B HASH
+The hash function to use for verifying archive integrity. This is
+passed to the
+.B \-H
+option of
+.BR fshash ,
+so it must name one of the hash functions supported by your Python's
+.B hashlib
+module.
+The default is
+.BR sha256 .
+.TP
+.B INDEXDB
+The name of a SQLite database initialized by
+.BR update-bkp-index (8)
+in which an index is maintained of which dumps are on which backup
+volumes. If the file doesn't exist, then no index is maintained. The
+default is
+.IB localstatedir /lib/bkp/index.db
+where
+.I localstatedir
+is the state directory configured at build time.
+.TP
.B MAXLOG
The number of log files to be kept for each filesystem. Old logfiles
are deleted to keep the total number below this bound. The default
value is 14.
.TP
+.B METADIR
+The metadata directory for the currently mounted backup volume.
+The default is
+.IB mntbkpdir /meta
+where
+.I mntbkpdir
+is the backup mount directory configured at build time.
+.TP
.B RSYNCOPTS
Command-line options to pass to
.BR rsync (1)
.I mntbkpdir
is the backup mount directory configured at build time.
.TP
-.B HASH
-The hash function to use for verifying archive integrity. This is
-passed to the
-.B \-H
-option of
-.BR fshash ,
-so it must name one of the hash functions supported by your Python's
-.B hashlib
-module. The default is
-.BR sha256 .
-.SS Hook functions
-The configuration file may define shell functions to perform custom
-actions at various points in the backup process.
+.B VOLUME
+The name of the current volume. If this is left unset, the volume name
+is read from the file
+.IB METADIR /volume
+once at the start of the backup run.
+.SS Hooks
+The configuration file can modify the behaviour of the backup in two
+main ways: by adding commands to hooks (see the
+.B addhook
+command); and by redefining shell functions.
+.PP
+The following hooks are defined.
.TP
-.BI "backup_precommit_hook " host " " fs " " date
+.BI "commit " host " " fs " " date
+Called during the commit procedure. The backup tree and manifest have
+been renamed into their proper places. Typically one would use this
+hook to rename files created in a corresponding
+.B precommit
+command.
+.TP
+.BI "end " rc
+The backup has completed;
+.B rsync-backup
+will exit with status
+.IR rc .
+.TP
+.BI "precommit " host " " fs " " date
Called after a backup has been verified complete and about to be
committed. The backup tree is in
.B new
A typical action would be to create a digital signature on the
manifest.
.TP
+.BI "setup " host " " fs " " date
+Called when a backup of a particular filesystem is about to start. It
+can return with code 99 to skip the backup.
+.TP
+.B "start"
+Invoked before performing any actual dumps (the first time
+.B host
+is run).
+.PP
+The following shell functions can be redefined by users.
+.TP
.BI "backup_commit_hook " host " " fs " " date
-Called during the commit procedure. The backup tree and manifest have
-been renamed into their proper places. Typically one would use this
-hook to rename files created by the
-.B backup_precommit_hook
-function.
+Called from the
+.B commit
+hook for compatibility.
+.TP
+.BI "backup_precommit_hook " host " " fs " " date
+Called from the
+.B precommit
+hook for compatibility.
.TP
.BR "whine " [ \-n ] " " \fItext\fR...
Called to report `interesting' events when the
At the top level is one directory for each client host. There are also
some special entries:
.TP
+.B \&.rsync-backup-store
+This file must be present in order to indicate that a backup volume is
+present (and not just an empty mount point).
+.TP
.B fshash.cache
The cache database used for improving performance of local file
hashing. There may be other
.PP
So don't use those names for your hosts.
.PP
-The next layer down contains a directory for each filesystem on the given host.
+The next layer down contains a directory for each filesystem on the
+given host.
.PP
The bottom layer contains a directory for each dump of that filesystem,
named with the date at which the dump was started (in ISO8601
.IB yyyy \(en mm \(en dd
format), together with associated files named
.IB date .* \fR.
+There is also a symbolic link
+.B last
+referring to the most recent backup of the filesystem.
.SH SEE ALSO
+.BR check-bkp-status (8),
.BR fshash (1),
.BR lvm (8),
.BR rfreezefs (8),
.BR rsync (1),
-.BR ssh (1).
+.BR ssh (1),
+.BR update-bkp-index (8).
.SH AUTHOR
Mark Wooding, <mdw@distorted.org.uk>
~mdw / rsync-backup / blobdiff