Rotera ZFS snapshots i FreeBSD: Difference between revisions

Revision as of 16:58, 11 March 2011

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+{{Box Fil|/root/bin/zfs-autosnap.sh|
+<pre>
+#!/bin/sh
+usage() {
+  cat <<EOF
+usage: ${0##*/} <label>
+  Rotates filesystem snapshots.  If filesystem has the property
+  org.freebsd:snap:<label>=<count>, increments all existing snapshots labeled
+  <label>.<num> and creates a new snapshot called <label>.0.  Destroys snapshot
+  numbered <label>.<count>.
+EOF
+  exit
+}
+# Default values
+: ${PROP:=org.freebsd:snap}
+# Parse command line
+[ ${#} -ne 1 ] && usage
+label=${1}
+issnap() {
+  [ "$(/sbin/zfs get -Ho value type "$1" 2>/dev/null)" = "snapshot" ]
+}
+# Iterate over all filesystems with ${PROP}:${label} > 0
+/sbin/zfs list -Ho name,${PROP}:${label} -t filesystem | \
+while read name value; do
+  [ $value -gt 0 ] 2>/dev/null || continue
+  # Destroy the oldest snapshot
+  value=$((${value} - 1))
+  snap="${name}@${label}"
+  issnap ${snap}.${value} && /sbin/zfs destroy ${snap}.${value}
+  # Increment existing snapshots
+  while [ ${value} -gt 0 ]; do
+    next=$((${value} - 1))
+    issnap ${snap}.${next} && /sbin/zfs rename "${snap}.${next}" "${snap}.${value}"
+    value=$next
+  done
+  # Make new snapshot
+  /sbin/zfs snapshot ${snap}.0
+done
+</pre>
+}}
 [[Category:FreeBSD]]