FreeBSD - Periodic ZFS Snapshots
Install zfs-periodic
Output
Message from zfs-periodic-1.0.20130213:
--
In order to enable periodic snapshots you need
to add these lines to your /etc/periodic.conf
hourly_output="root"
hourly_show_success="NO"
hourly_show_info="YES"
hourly_show_badconfig="NO"
hourly_zfs_snapshot_enable="YES"
hourly_zfs_snapshot_pools="tank"
hourly_zfs_snapshot_keep=6
daily_zfs_snapshot_enable="YES"
daily_zfs_snapshot_pools="tank"
daily_zfs_snapshot_keep=7
weekly_zfs_snapshot_enable="YES"
weekly_zfs_snapshot_pools="tank"
weekly_zfs_snapshot_keep=5
monthly_zfs_snapshot_enable="YES"
monthly_zfs_snapshot_pools="tank"
monthly_zfs_snapshot_keep=2
To get hourly snapshots you also need to add
something like this to /etc/crontab:
2 * * * * root periodic hourly
Customize /etc/periodic.conf
# Hourly options
hourly_output="root" # user or /file
hourly_show_success="NO" # scripts returning 0
hourly_show_info="YES" # scripts returning 1
hourly_show_badconfig="NO" # scripts returning 2
# 000.zfs-snapshot
hourly_zfs_snapshot_enable="YES"
hourly_zfs_snapshot_pools="zroot" # space seperated list of pools or datasets
hourly_zfs_snapshot_keep=24
hourly_zfs_snapshot_skip="" # space seperated list of datasets to skip
# Quarter hourly options
# 000.zfs-snapshot
quarter_hourly_zfs_snapshot_enable="YES"
quarter_hourly_zfs_snapshot_pools="zroot"
quarter_hourly_zfs_snapshot_keep=4
quarter_hourly_zfs_snapshot_skip=""
# Daily options
# 000.zfs-snapshot
daily_zfs_snapshot_enable="YES"
daily_zfs_snapshot_pools="zroot"
daily_zfs_snapshot_keep=7
daily_zfs_snapshot_skip=""
# 404.status-zfs
daily_status_zfs_enable="YES"
# Weekly options
# 000.zfs-snapshot
weekly_zfs_snapshot_enable="YES"
weekly_zfs_snapshot_pools="zroot"
weekly_zfs_snapshot_keep=5
weekly_zfs_snapshot_skip=""
# Monthly options
# 000.zfs-snapshot
monthly_zfs_snapshot_enable="YES"
monthly_zfs_snapshot_pools="zroot"
monthly_zfs_snapshot_keep=3
monthly_zfs_snapshot_skip=""
# 998.zfs-scrub
monthly_zfs_scrub_enable="YES"
monthly_zfs_scrub_pools="zroot"
Customize /etc/crontab
# /etc/crontab - root's crontab for FreeBSD
#
#
SHELL=/bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin
#
#minute hour mday month wday who command
#
# Save some entropy so that /dev/random can re-seed on boot.
*/11 * * * * operator /usr/libexec/save-entropy
#
# Rotate log files every hour, if necessary.
0 * * * * root newsyslog
#
# Perform daily/weekly/monthly maintenance.
*/15 * * * * root periodic quarter_hourly
1 * * * * root periodic hourly
1 3 * * * root periodic daily
15 4 * * 6 root periodic weekly
30 5 1 * * root periodic monthly
#
# Adjust the time zone if the CMOS clock keeps local time, as opposed to
# UTC time. See adjkerntz(8) for details.
1,31 0-5 * * * root adjkerntz -a
Enable quarter hourly snapshots
see https://github.com/ross/zfs-periodic/pull/10/commits/b37103444a0dcac58937e134cbbeb347831b967a and https://evilham.com/en/blog/2023-ZFS-replication-tools/ for more details
doas mkdir /usr/local/etc/periodic/quarter_hourly
doas cp /usr/local/etc/periodic/hourly/000.zfs-snapshot /usr/local/etc/periodic//quarter_hourly/000.zfs-snapshot
customize /usr/local/etc/periodic//quarter_hourly/000.zfs-snapshot
-> change hourlyto quarter_hourly
#!/bin/sh
# If there is a global system configuration file, suck it in.
#
if [ -r /etc/defaults/periodic.conf ]
then
. /etc/defaults/periodic.conf
source_periodic_confs
fi
pools=$quarter_hourly_zfs_snapshot_pools
if [ -z "$pools" ]; then
pools='tank'
fi
keep=$quarter_hourly_zfs_snapshot_keep
if [ -z "$keep" ]; then
keep=6
fi
case "$quarter_hourly_zfs_snapshot_enable" in
[Yy][Ee][Ss])
. /usr/local/bin/zfs-snapshot
do_snapshots "$pools" $keep 'quarter_hourly' "$quarter_hourly_zfs_snapshot_skip"
;;
*)
;;
esac
/usr/local/bin/zfs-snapshot
#!/bin/sh
# take the appropriately named snapshot
create_snapshot()
{
pool=$1
case "$type" in
quarter_hourly)
now=`date +"$type-%Y-%m-%d-%H-%M"`
;;
hourly)
now=`date +"$type-%Y-%m-%d-%H"`
;;
daily)
now=`date +"$type-%Y-%m-%d"`
;;
weekly)
now=`date +"$type-%Y-%U"`
;;
monthly)
now=`date +"$type-%Y-%m"`
;;
yearly)
now=`date +"$type-%Y"`
;;
*)
echo "unknown snapshot type: $type"
exit 1
esac
# enumerate datasets under this pool or dataset, skip excluded datasets if requested
if [ -n "$skip" ]; then
egrep="($(echo $skip | sed "s/ /|/g"))"
datasets=$(zfs list -r -H -o name $pool | egrep -v "$egrep")
else
datasets=$(zfs list -r -H -o name $pool)
fi
# loop through datasets, do snapshots of each
for dataset in $datasets; do
snapshot="$dataset@$now"
# look for an existing snapshot with this name
if zfs list $snapshot > /dev/null 2>&1; then
echo " snapshot $snapshot already exists, skipping..."
else
echo " taking snapshot: $snapshot"
zfs snapshot $snapshot
fi
done
}
# delete the named snapshot
delete_snapshot()
{
snapshot=$1
echo " destroying old snapshot, $snapshot"
zfs destroy -r $snapshot
}
# take a type snapshot of pool, keeping keep old ones
do_pool()
{
pool=$1
keep=$2
type=$3
skip=$4
# create the regex matching the type of snapshots we're currently working
# on
case "$type" in
quarter_hourly)
# quarter_hourly-2009-01-01-00-15
regex="^$pool@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]-[0-9][0-9]-[0-9][0-9]$"
;;
hourly)
# hourly-2009-01-01-00
regex="^$pool@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]-[0-9][0-9]$"
;;
daily)
# daily-2009-01-01
regex="^$pool@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]$"
;;
weekly)
# weekly-2009-01
regex="^$pool@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]"
;;
monthly)
# monthly-2009-01
regex="^$pool@$type-[0-9][0-9][0-9][0-9]-[0-9][0-9]"
;;
yearly)
# yearly-2009
regex="^$pool@$type-[0-9][0-9][0-9][0-9]"
;;
*)
echo "unknown snapshot type: $type"
exit 1
esac
create_snapshot $pool $type
# get a list of all of the snapshots of this type sorted alpha, which
# effectively is increasing date/time
# (using sort as zfs's sort seems to have bugs)
snapshots=`zfs list -H -o name -t snapshot | sort | grep $regex`
# count them
count=`echo $snapshots | wc -w`
if [ $count -ge 0 ]; then
# how many items should we delete
delete=`expr $count - $keep`
count=0
# walk through the snapshots, deleting them until we've trimmed deleted
for snapshot in $snapshots; do
if [ $count -ge $delete ]; then
break
fi
delete_snapshot $snapshot
count=`expr $count + 1`
done
fi
}
# take snapshots of type, for pools, keeping keep old ones,
do_snapshots()
{
pools=$1
keep=$2
type=$3
skip=$4
echo ""
echo "Doing zfs $type snapshots:"
for pool in $pools; do
do_pool $pool $keep $type "$skip"
done
}