create-timed-lvm-snapshot.sh

#!/bin/bash

set -e

OPTIND=1 # Reset in case getopts has been used previously in the shell.

# argument defaults
snapshotSize="10G"
snapshotTime=$(date +%Y%m%d-%H%M%S)
volumeGroup="/dev/vg0/"
logicalVolume="mongodb"
doCleanup=false

while getopts "l:s:c" opt; do
    case "$opt" in
    l)
      logicalVolume=$OPTARG
      ;;
    s)
      snapshotSize=$OPTARG
      ;;
    c)
      doCleanup=true
      ;;
    \?)
      exit 1
      ;;
    esac
done

lvToSnapshot="${volumeGroup}${logicalVolume}"
snapshotPrefix="${logicalVolume}-snap"

echo "Creating LVM snapshot ${snapshotPrefix}-${snapshotTime}"
bash -c "set -x;lvcreate --size $snapshotSize --snapshot --name ${snapshotPrefix}-${snapshotTime} $lvToSnapshot"

if $doCleanup
then
  echo "Looking for old LVM snapshots to remove"
  for snapshot in `lvscan | grep -o -i -P "(?<=snapshot ')${volumeGroup}${snapshotPrefix}-[[:digit:]]{8}-[[:digit:]]{6}"`
  do
    # if the snapshot is older than the one we just created, get rid of it
    if [ ${snapshot:(-15)} \< $snapshotTime ]
    then
      echo "Removing $snapshot"
      echo "Make sure it's not mounted"
      set +e
      bash -c "set -x;umount $snapshot"
      set -e
      echo "Remove"
      bash -c "set -x;lvremove $snapshot" <<HERE
y
HERE
    fi
  done
fi