Automatically delete old NetApp snapshots left by backups

Backup software may sometimes leave behind a snapshot.  This can increase the space consumption a lot over time.

Here's a script that can be run against NetApp filers to clean up those "stale" backups.  Note that in my case, I configured CommVault to name the snapshots with the string "snapshot_for_backup", though the default is just "ndmp".  You may change that as needed.

#!/bin/bash

# This script is to look for snaps that are left over from backups, that # are no longer in use, and delete them.

# This script requires two parameters:

# snap_cleanup     (list or delete all stale snaps on the specified servers)

NasUser="root"

SnapshotString="snapshot_for_backup"

SshIdentityFile="/root/.ssh/id_rsa_auslxfs00_rsync"

SshBinary=/usr/bin/ssh

# This function receives a volume name as a parameter, and returns # the number of snaps that are elligible for deletion, defined by being:

#                             1. Having a certain string in the snapshot name;

#                             2. Not marked as "busy"

function CountStaleSnaps ()

{

                local VolToCheck=$1

                local StaleSnaps=`$SshCmd "snap list $VolToCheck" | grep $SnapshotString | grep -v "busy" | wc -l`

                if [ $? -ne 0 ]; then

                {

                                echo "getting count of elligible snapshots returned an error"

                                exit 1

                } else

                {

                                echo $StaleSnaps

                } fi

}

# Function GetStaleSnapNames

# This function creates, given a volume name, an array of snapshots that are # candidates for deletion.

# Parameters

#             1. volume to check

function GetStaleSnapNames ()

{

                local Volume=$1

                StaleSnapNames=( $($SshCmd "snap list $Volume" | grep $SnapshotString| grep -v busy | cut -c 39- | cut -f 1 -d " ") )

                if [ $? -ne 0 ]; then

                {

                                echo "getting names of elligible snapshots returned an error"

                                exit 1

                } else

                {

                                printf -- '%s\n' "${StaleSnapNames[@]}"

                } fi

}

# Function DelStaleSnaps

# This function deletes stale snaps for the Volume name passed to it.

# Parameters

#  1. volume

#  2. snapshot_name

function DelStaleSnaps ()

{

                local Volume=$1

                local SnapToDelete=$2

                $SshCmd "snap delete $Volume $SnapToDelete"

                if [ $? -ne 0 ]; then

                {

                                echo "error deleting snapshot $Volume:$SnapToDelete"

                                exit 1

                } else

                {

                                echo "successfully deleted snapshot $Volume:$SnapToDelete"

                } fi

}

# Parse command line parameters

case $2 in

                "")

                                echo "ERROR: you must specify as a second parameter a host name on which you want to delete snapshots."

                                ;;

                *)

                                NasName=$2

                                ;;

esac

case $1 in

                list)

                                Operation=list

                                ;;

                delete)

                                Operation=delete

                                ;;

                *)

                                echo "ERROR: invalid operation specified on command line.  Please specify either 'list' or 'delete' followed by the servername on which you want to delete the snapshots."

                                exit 1

                                ;;

esac

SshCmd="/usr/bin/ssh -i $SshIdentityFile $NasUser@$NasName"

VolumesToCheck=( `$SshCmd "vol status -b" | cut -f 1 -d " " | egrep -v "Volume|-----"` )

for CurrentVol in ${VolumesToCheck[@]}; do {

                echo -n "checking $NasName:$CurrentVol... "

                StaleSnaps=`CountStaleSnaps $CurrentVol`

                echo $StaleSnaps            

                if [ $Operation = list ]; then

                                if [ $StaleSnaps -ne 0 ]; then

                                                GetStaleSnapNames $CurrentVol |  awk '{ print "    " $1 }'

                                fi

                elif [ $Operation = delete ]; then

                                GetStaleSnapNames $CurrentVol

                                ArrayOfSnaps=( $(GetStaleSnapNames $CurrentVol) )

                                for TargetSnap in `printf -- '%s\n' "${ArrayOfSnaps[@]}"`; do

                                                                DelStaleSnaps $CurrentVol $TargetSnap

                                done

                fi

                               

}; done