Take LVM snapshot / cycle old ones out at specified interval

lvmbak.sh

#!/bin/bash
# Take LVM snapshot / cycle old ones out at specified interval

# Set executable: chmod +x lvmbak.sh

# Make sure to setup sudo correctly:
#  # visudo
#    <USER> ALL= NOPASSWD: /sbin/lvcreate
#    <USER> ALL= NOPASSWD: /sbin/lvremove
#    <USER> ALL= NOPASSWD: /sbin/lvs

# Setup to run as a cronjob:
#  (in this case daily at 11AM)
#  $ crontab -e
#    0 11 * * * /home/mmorsi/lvmbak.sh

KEEP_PERIODS=3             # number of periods to keep snapshot
PERIOD_LENGTH=86400        # in seconds
VG="dnp00"                 # LVM volume group we are snapshoting
LV="dnv1"                  # Name of LVM-volume to take a snapshot of
BACKUP_PREFIX="dnv1-snap-" # Prefix of snapshot volume name.
PV="/dev/sdd"              # Physical volume to create snapshot on
SIZE="150G"                # Amount of disk space to allocate for the snapshot

# Create new snapshot
TODAY="$(date +%s)" 
NEW_VOLUME="$BACKUP_PREFIX$TODAY" 
if ! lvs | grep -q -F "$NEW_VOLUME"; then
    sudo /sbin/lvcreate --size $SIZE --permission r --snapshot "$VG/$LV" --name "$NEW_VOLUME"  $PV
else
    echo "Backup already exists: $NEW_VOLUME" 
fi

# Clean old snapshots.
sudo /sbin/lvs -o lv_name --noheadings | sed -n "s@$BACKUP_PREFIX@@p" | while read DATE; do
    TS_DATE=$(date -d "@$DATE" +%s)
    TS_NOW=$(date +%s)
    AGE=$(( (TS_NOW - TS_DATE) / $PERIOD_LENGTH))
    if [ "$AGE" -ge "$KEEP_PERIODS" ]; then
        VOLNAME="$BACKUP_PREFIX$DATE" 
        sudo /sbin/lvremove -f "$VG/$VOLNAME" 
    fi
done