This page contains scripts, links to other sites and "howto" docs
that the staff at Open Technologies Inc. commonly use.
You are free to use this material as you wish, but we take NO responsibility
for your proper or improper use of this material.  See Limitation of Liability below.
-----------------------------------------------------------------------------
#!/bin/sh

# Description: Create and deletes a rotating list of zfs snapshots
#              Can be daily, weekly, monthly, etc. or a combination
#              and depends upon what you put in the cron job.
#------------------------------------------------------------------
# Author: Phillip Fiedler
# Created: 1/29/07
# Revised: 2/9/07
# Revised: 10/10/07 v0.2
# Revised: 11/23/09 v0.3
# Revised:          v0.4 (this version needs to move the snapshots.cur to the filesystems
#                         so when the zpool moves to another server, the snapshot logs go also.
#------------------------------------------------------------------

# Number of snapshots to save/rotate
numsnaps="7"

# Identifier (eg., daily, weekly, monthly, etc.)
id=daily

cur="/opt/scripts/snapshots/$id/snapshots.cur"
new="/opt/scripts/snapshots/$id/snapshots.new"
lst="/opt/scripts/snapshots/$id/zfs.list"

#------------------------------------------------------------------

# Generate ZFS filesystem list if one wasn't given on the command line
if [ "$1" = "" ]; then
   zfs list | awk '{print $1}' | grep '\/' | grep -v '@' > $lst
fi

# Check to make sure the list file exists
if [ ! -f $lst ]; then
   echo "Usage: Must provide a list of zfs filesystems in '$lst' for snapshot rotation."
   echo "       Error: Unable to use 'zfs list | awk '{print \$1}' | grep '\/' > $lst' to create list."
   echo ""
   exit 0
fi

# Create the "cur" file if it doesn't exist
if [ ! -f $cur ]; then
   touch $cur
fi

# Get Current Date and put in the "snapshots.new" file
newsnap="$id-"`date '+%m%d%y-%H%M%S'`
echo $newsnap > $new

# If the current snapshot file exists and has recorded snapshot history
if [ -f $cur -a "`cat $cur | wc -l | awk '{print $1}`" -ge "$numsnaps" ]; then

  # Put newest snapshot dates in new snapshot list file
  head -"`echo $numsnaps-1 | bc`" $cur >> $new

  # Get oldest snapshot date
  oldsnap=`tail -1 $cur`

  # Remove current snapshot list file
  rm $cur

else
  cat $cur >> $new
fi

# Rename new to current
mv $new $cur

# Create new snapshots
for i in `cat $lst`; do
    zfs snapshot $i@$newsnap
done

# Delete the oldest snapshots
if [ "$oldsnap" != "" ]; then
   for i in `cat $lst`; do
       zfs destroy $i@$oldsnap
  done
fi

exit 0 
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