FreeBSD/scripts/zfs-prune-snapshots

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2020-02-25 11:28:31 -08:00
#!/usr/bin/env bash
#
# script to prune zfs snapshots over a given age
#
# Author: Dave Eddy <dave@daveeddy.com>
# Date: November 20, 2015
# License: MIT
VERSION='v1.0.1'
usage() {
local prog=${0##*/}
cat <<-EOF
usage: $prog [-hnv] [-p <prefix] <time> [[dataset1] ...]
remove snapshots from one or more zpools that match given criteria
examples
# $prog 1w
remove snapshots older than a week across all zpools
# $prog -vn 1w
same as above, but with increased verbosity and without
actually deleting any snapshots (dry-run)
# $prog 3w tank1 tank2/backup
remove snapshots older than 3 weeks on tank1 and tank2/backup.
note that this script will recurse through *all* of tank1 and
*all* datasets below tank2/backup
# $prog -p 'autosnap_' 1M zones
remove snapshots older than a month on the zones pool that start
with the string "autosnap_"
timespec
the first argument denotes how old a snapshot must be for it to
be considered for deletion - possible specifiers are
s seconds
m minutes
h hours
d days
w weeks
M months
y years
options
-h print this message and exit
-n dry-run, don't actually delete snapshots
-p <prefix> snapshot prefix string to match
-q quiet, do not printout removed snapshots
-v increase verbosity
-V print the version number and exit
EOF
}
debug() {
((verbosity >= 1)) && echo "$@"
return 0
}
# given a time in seconds, return the "human readable" string
human() {
local seconds=$1
if ((seconds < 0)); then
((seconds *= -1))
fi
local times=(
$((seconds / 60 / 60 / 24 / 365)) # years
$((seconds / 60 / 60 / 24 / 30)) # months
$((seconds / 60 / 60 / 24 / 7)) # weeks
$((seconds / 60 / 60 / 24)) # days
$((seconds / 60 / 60)) # hours
$((seconds / 60)) # minutes
$((seconds)) # seconds
)
local names=(year month week day hour minute second)
local i
for ((i = 0; i < ${#names[@]}; i++)); do
if ((${times[$i]} > 1)); then
echo "${times[$i]} ${names[$i]}s"
return
elif ((${times[$i]} == 1)); then
echo "${times[$i]} ${names[$i]}"
return
fi
done
echo '0 seconds'
}
dryrun=false
verbosity=0
prefix=
quiet=false
while getopts 'hnqp:vV' option; do
case "$option" in
h) usage; exit 0;;
n) dryrun=true;;
p) prefix=$OPTARG;;
q) quiet=true;;
v) ((verbosity++));;
V) echo "$VERSION"; exit 0;;
*) usage; exit 1;;
esac
done
shift "$((OPTIND - 1))"
# extract the first argument - the timespec - and
# convert it to seconds
t=$1
time_re='^([0-9]+)([smhdwMy])$'
seconds=
if [[ $t =~ $time_re ]]; then
# ex: "21d" becomes num=21 spec=d
num=${BASH_REMATCH[1]}
spec=${BASH_REMATCH[2]}
case "$spec" in
s) seconds=$((num));;
m) seconds=$((num * 60));;
h) seconds=$((num * 60 * 60));;
d) seconds=$((num * 60 * 60 * 24));;
w) seconds=$((num * 60 * 60 * 24 * 7));;
M) seconds=$((num * 60 * 60 * 24 * 30));;
y) seconds=$((num * 60 * 60 * 24 * 365));;
*) echo "error: unknown spec '$spec'" >&2; exit 1;;
esac
elif [[ -z $t ]]; then
echo 'error: timespec must be specified as the first argument' >&2
exit 1
else
echo "error: failed to parse timespec '$t'" >&2
exit 1
fi
shift
pools=("$@")
now=$(date +%s)
code=0
while read -r creation snapshot; do
# ensure optional prefix matches
snapname=${snapshot#*@}
if [[ -n $prefix && $prefix != "${snapname:0:${#prefix}}" ]]; then
debug "skipping $snapshot: doesn't match prefix $prefix"
continue
fi
# ensure snapshot is older than the cutoff time
delta=$((now - creation))
human=$(human "$delta")
if ((delta <= seconds)); then
debug "skipping $snapshot: $human old"
continue
fi
# remove the snapshot
if ! $quiet || $dryrun; then
echo -n "removing $snapshot: $human old"
fi
if $dryrun; then
echo ' <dry-run: no action taken>'
else
if ! $quiet; then
echo
fi
zfs destroy "$snapshot" || code=1
fi
done < <(zfs list -Hpo creation,name -t snapshot -r "${pools[@]}")
exit "$code"