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ZETABACK(1) |
User Contributed Perl Documentation |
ZETABACK(1) |
zetaback - perform backup, restore and retention policies for ZFS backups.
zetaback -v
zetaback [-l|-s|-sx|-sv|-svv] [--files] [-c conf] [-d] [-h host] [-z zfs]
zetaback -a [-c conf] [-d] [-h host] [-z zfs]
zetaback -b [-ff] [-fi] [-x] [-c conf] [-d] [-n] [-h host] [-z zfs]
zetaback -x [-b] [-c conf] [-d] [-n] [-h host] [-z zfs]
zetaback -r [-c conf] [-d] [-n] [-h host] [-z zfs] [-t timestamp]
[-rhost host] [-rzfs fs]
The zetaback program orchestrates the backup (either full or incremental)
of remote ZFS filesystems to a local store. It handles frequency requirements
for both full and incemental backups as well as retention policies. In
addition to backups, the zetaback tool allows for the restore of any
backup to a specified host and zfs filesystem.
The non-optional action command line arguments define the invocation purpose of
zetaback. All other arguments are optional and refine the target of the
action specified.
The following arguments have the same meaning over several actions:
- -c <conf>
- Use the specified file as the configuration file. The default file, if
none is specified is /usr/local/etc/zetaback.conf. The prefix of this file
may also be specified as an argument to the configure script.
- -d
- Enable debugging output.
- -n
- Don't actually perform any remote commands or expunging. This is useful
with the -d argument to ascertain what would be done if the command was
actually executed.
- -t <timestamp>
- Used during the restore process to specify a backup image from the desired
point in time. If omitted, the command becomes interactive. This timestamp
is a UNIX timestamp and is shown in the output of the -s and -sx
actions.
- -rhost <host>
- Specify the remote host that is the target for a restore operation. If
omitted the command becomes interactive.
- -rzfs <zfs>
- Specify the remote ZFS filesystem that is the target for a restore
operation. If omitted the command becomes interactive.
- -h <host>
- Filters the operation to the host specified. If <host> is of the
form /pattern/, it matches 'pattern' as a perl regular expression against
available hosts. If omitted, no limit is enforced and all hosts are used
for the action.
- -z <zfs>
- Filters the operation to the zfs filesystem specified. If <zfs> is
of the form /pattern/, it matches 'pattern' as a perl regular expression
against available zfs filesystems. If omitted, no filter is enforced and
all zfs filesystems are used for the action.
- -v
- Show the version.
- -l
- Show a brief listing of available backups.
- -s
- Like -l, -s will show a list of backups but provides additional
information about the backups including timestamp, type (full or
incremental) and the size on disk.
- -sx
- Shows an extended summary. In addition to the output provided by the -s
action, the -sx action will show detail for each availble backup. For full
backups, the detail will include any more recent full backups, if they
exist. For incremental backups, the detail will include any incremental
backups that are more recent than the last full backup.
- -sv
- Display all backups in the current store that violate the configured
backup policy. This is where the most recent full backup is older than
full_interval seconds ago, or the most recent incremental backup is older
than backup_interval seconds ago.
If, at the time of the most recent backup, a filesystem no
longer exists on the server (because it was deleted), then backups of
this filesystem are not included in the list of violators. To include
these filesystems, use the -svv option instead.
- -svv
- The violators summary will exclude backups of filesystems that are no
longer on the server in the list of violators. Use this option to include
those filesystems.
- --files
- Display the on-disk file corresponding to each backup named in the output.
This is useful with the -sv flag to name violating files. Often times,
violators are filesystems that have been removed on the host machines and
zetaback can no longer back them up. Be very careful if you choose to
automate the removal of such backups as filesystems that would be backed
up by the next regular zetaback run will often show up as violators.
- -a
- Performs an archive. This option will look at all eligible backup points
(as restricted by -z and -h) and move those to the configured archive
directory. The recommended use is to first issue -sx --files then
carefully review available backup points and prune those that are
unneeded. Then invoke with -a to move only the remaining
"desired" backup points into the archives. Archived backups do
not appear in any listings or in the list of policy violators generated by
the -sv option. In effect, they are no longer "visible" to
zetaback.
- -b
- Performs a backup. This option will investigate all eligible hosts, query
the available filesystems from the remote agent and determine if any such
filesystems require a new full or incremental backup to be taken. This
option may be combined with the -x option (to clean up afterwards.)
- -ff
- Forces a full backup to be taken on each filesystem encountered. This is
used in combination with -b. It is recommended to use this option only
when targeting specific filesystems (via the -h and -z options.) Forcing a
full backup across all machines will cause staggered backups to coalesce
and could cause performance issues.
- -fi
- Forces an incremental backup to be taken on each filesystem encountered.
This is used in combination with -b. It is recommended to use this option
only when targeting specific filesystems (via the -h and -z options.)
Forcing an incremental backup across all machines will cause staggered
backups to coalesce and could cause performance issues.
- -x
- Perform an expunge. This option will determine which, if any, of the local
backups may be deleted given the retention policy specified in the
configuration.
- -r
- Perform a restore. This option will operate on the specified backup and
restore it to the ZFS filesystem specified with -rzfs on the host
specified with the -rhost option. The -h, -z and -t options may be used to
filter the source backup list. If the filtered list contains more than one
source backup image, the command will act interactively. If the -rhost and
-rzfs command are not specified, the command will act interactively.
When running interactively, you can choose multiple
filesystems from the list using ranges. For example 1-4,5,10-11. If you
do this, zetaback will enter multi-restore mode. In this mode it will
automatically select the most recent backup, and restore filesystems in
bulk.
In multi-restore mode, you have the option to specify a base
filesystem to restore to. This filesystem will be added as a prefix to
the original filesystem name, so if you picked a prefix of data/restore,
and one of the filesystems you are restoring is called
data/set/myfilesystem, then the filesystem will be restored to
data/restore/data/set/myfilesystem.
Note that, just like in regular restore mode, zetaback won't
create intermediate filesystems for you when restoring, and these should
either exist beforehand, or you should make sure you pick a set of
filesystems that will restore the entire tree for you, for example, you
should restore data as well as data/set before restoring
data/set/foo.
The zetaback configuration file consists of a default stanza, containing
settings that can be overridden on a per-host basis. A stanza begins either
with the string 'default', or a fully-qualified hostname, with settings
enclosed in braces ({}). Single-line comments begin with a hash ('#'), and
whitespace is ignored, so feel free to indent for better readability. Every
host to be backed up must have a host stanza in the configuration file.
In addition to the default and host stanzas, the configuration file can also
contain 'class' stanzas. Classes allow you to override settings on a
per-filesystem basis rather than a per-host basis. A class stanza begins with
the name of the class, and has a setting 'type = class'. For example:
myclass {
type = class
store = /path/to/alternate/store
}
To add a filesystem to a class, set a zfs user property on the
relevant filesystem. This must be done on the server that runs the zetaback
agent, and not the zetaback server itself.
zfs set com.omniti.labs.zetaback:class=myclass pool/fs
Note that user properties (and therefore classes) are are only
available on Solaris 10 8/07 and newer, and on Solaris Express build 48 and
newer. Only the server running the agent needs to have user property
support, not the zetaback server itself.
The following settings can be included in a class stanza. All
other settings will be ignored, and their default (or per host) settings
used instead:
- store
- full_interval
- backup_interval
- retention
- dataset_backup
- violator_grace_period
The following settings are valid in both the default and host scopes:
- store
- The base directory under which to keep backups. An interpolated variable
'%h' can be used, which expands to the hostname. There is no default for
this setting.
- archive
- The base directory under which archives are stored. The format is the same
as the store setting. This is the destination to which files are relocated
when issuing an archive action (-a).
- agent
- The location of the zetaback_agent binary on the host. There is no default
for this setting.
- time_format
- All timestamps within zetaback are in UNIX timestamp format. This setting
provides a string for formatting all timestamps on output. The sequences
available are identical to those in strftime(3). If not specified,
the default is '%Y-%m-%d %H:%M:%S'.
- backup_interval
- The frequency (in seconds) at which to perform incremental backups. An
incremental backup will be performed if the current time is more than
backup_interval since the last incremental backup. If there is no full
backup for a particular filesystem, then a full backup is performed. There
is no default for this setting.
- full_interval
- The frequency (in seconds) at which to perform full backups. A full backup
will be performed if the current time is more than full_interval since the
last full backup.
- retention
- The retention time (in seconds) for backups. This can be a simple number,
in which case all backups older than this will be expunged.
The retention specification can also be more complex, and
consist of pairs of values separated by a comma. The first value is a
time period in seconds, and the second value is how many backups should
be retained within that period. For example:
retention = 3600,4;86400,11
This will keep up to 4 backups for the first hour, and an
additional 11 backups over 24 hours. The times do not stack. In other
words, the 11 backups would be kept during the period from 1 hour old to
24 hours old, or one every 2 hours.
Any backups older than the largest time given are deleted. In
the above example, all backups older than 24 hours are deleted.
If a second number is not specified, then all backups are kept
within that period.
Note: Full backups are never deleted if they are depended upon
by an incremental. In addition, the most recent backup is never deleted,
regardless of how old it is.
This value defaults to (14 * 86400), or two weeks.
- compressionlevel
- Compress files using gzip at the specified compression level. 0 means no
compression. Accepted values are 1-9. Defaults to 1 (fastest/minimal
compression.)
- ssh_config
- Full path to an alternate ssh client config. This is useful for specifying
a less secure but faster cipher for some hosts, or using a different
private key. There is no default for this setting.
- dataset_backup
- By default zetaback backs zfs filesystems up to files. This option lets
you specify that the backup go be stored as a zfs dataset on the backup
host.
- offline
- Setting this option to 1 for a host will mark it as being 'offline'. Hosts
that are marked offline will not be backed up, will not have any old
backups expunged and will not be included in the list of policy violators.
However, the host will still be shown when listing backups and
archiving.
- violator_grace_period
- This setting controls the grace period used when deciding if a backup has
violated its backup window. It is used to prevent false positives in the
case where a filesystem is still being backed up. For example, if it is 25
hours since the last daily backup, but the daily backup is in progress,
the grace period will mean that it is not shown in the violators list.
Like all intervals, this period is in seconds. The default is
21600 seconds (6 hours).
The following settings are only valid in the default scope:
- process_limit
- This setting limits the number of concurrent zetaback processes that can
run at one time. Zetaback already has locks on hosts and datasets to
prevent conflicting backups, and this allows you to have multiple zetaback
instances running in the event a backup takes some time to complete, while
still keeping a limit on the resources used. If this configuration entry
is missing, then no limiting will occur.
This config results in backups stored in /var/spool/zfs_backups, with a
subdirectory for each host. Incremental backups will be performed
approximately once per day, assuming zetaback is run hourly. Full backups will
be done once per week. Time format and retention are default.
default {
store = /var/spool/zfs_backups/%h
agent = /usr/local/bin/zetaback_agent
backup_interval = 83000
full_interval = 604800
}
host1 {}
host2 {}
Here, host1's and host2's agents are found in different places, and host2's
backups should be stored in a different path.
default {
store = /var/spool/zfs_backups/%h
agent = /usr/local/bin/zetaback_agent
backup_interval = 83000
full_interval = 604800
}
host1 {
agent = /opt/local/bin/zetaback_agent
}
host2 {
store = /var/spool/alt_backups/%h
agent = /www/bin/zetaback_agent
}
- zetaback.conf
- The main zetaback configuration file. The location of the file can be
specified on the command line with the -c flag. The prefix of this file
may also be specified as an argument to the configure script.
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