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UNTITLED() LOCAL UNTITLED() NAME periodic-snapshot -- run periodic UFS/ZFS backup snapshot maintenance task SYNOPSIS periodic-snapshot DESCRIPTION The periodic-snapshot utility is intended to be called by cron(8) to create and expire UFS/ZFS backup snapshots through the snapshot(8) command accord- ing to the snapshot_enable and snapshot_schedule settings from peri- odic.conf(5). The system /etc/crontab will typically have entries for periodic-snapshot similar to the following example: # do hourly/daily/weekly maintenance of FreeBSD UFS/ZFS snapshots 0 * * * * root periodic-snapshot hourly 0 0 * * * root periodic-snapshot daily 0 0 * * 0 root periodic-snapshot weekly The /etc/defaults/periodic.conf system registry will typically contain the following defaults which keep periodic-snapshot disabled by default: snapshot_enable="NO" snapshot_schedule="" The snapshot_schedule variable values have to conform to the following grammar: <schedule> ::= <entry>* <entry> ::= <fs> ("," <fs>)* ":" <spec> <fs> ::= /^.*$/ <spec> ::= <gen_weekly> ":" <gen_daily> ":" <gen_hourly> <gen_weekly> ::= <generation> <gen_daily> ::= <generation> <gen_hourly> ::= <generation> ("@" <hour> ("," <hour>)*)? <generation> ::= /^[0-9]+$/ <hour> ::= /^(0?[0-9]|1[0-9]|2[0-3])$/ The number of all added "generation" numbers of a filesystem cannot be larger than 20 because this is the maximum number of snapshots which can be created on a UFS/ZFS filesystem. A "generation" number of "0" disables the creation of backup snapshots. The used schedule heavily depends on how much generations of snapshots should be kept, which in turn depends on how much disk space is available. FILES /etc/crontab the periodic-snapshot utility is typically called via entries in the system default cron(8) table. /etc/defaults/periodic.conf system registry containing variables that con- trol the behaviour of periodic-snapshot. /etc/periodic.conf this file contains local overrides for the de- fault periodic-snapshot configuration. EXAMPLES In order to configure UFS/ZFS backup snapshot creation, add lines to /etc/periodic.conf similar to: snapshot_enable="YES" snapshot_schedule="/,/usr:2:1:0 /var:0:2:4 /home:2:6:8@8,12,16,20" This schedules the following UFS/ZFS backup snapshots: 2 weekly (weekly.[01]) and 1 daily (daily.0) generation of snapshots on the / and /usr filesystems, two daily (daily.[01]) and 4 hourly (hourly.[0123]) gen- erations of snapshots on the /var filesystem, and 2 weekly (weekly.[01]), 6 daily (daily.[0123456]) and 8 hourly (hourly.[01234567]) generations of snapshots on the /home filesystem. While the hourly snapshots on /var are created every hour, the hourly snapshots on /home are created on 08:00, 12:00, 16:00 and 20:00 only. SEE ALSO sh(1), crontab(5), periodic.conf(5), cron(8), snapshot(8), http://peo- ple.freebsd.org/~rse/snapshot/. HISTORY The periodic-snapshot utility first appeared in FreeBSD. AUTHORS Ralf S. Engelschall <rse@FreeBSD.org> FreeBSD ports 15.quarterly September 03, 2004 PERIODIC-SNAPSHOT(8)
NAME | SYNOPSIS | DESCRIPTION | FILES | EXAMPLES | SEE ALSO | HISTORY | AUTHORS
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