Reclaim Disk Space from Deleted XenServer Snapshots and Clones

Running this script will incur some downtime for the VM, due the suspend/resume operations performed.

This instructions are for XenServer 5.6 and later

Citrix recommends that you back up the VM on which you will run the space reclamation tool. You can use the XenCenter export option for this purpose.

Run the following command from the XenServer CLI:

xe host-call-plugin host-uuid=<host-UUID> plugin=coalesce-leaf fn=leaf-coalesce args:vm_uuid=<VM-UUID>

The amount of time required varies based on the amount of data written to the disk since the last snapshot. Smaller VMs (that is, 10 GB or less) take less than a minute.

If the Virtual Disk Images (VDIs) to be coalesced are on shared storage, you must execute the off-line coalesce tool on the pool master.

To get Pool Master UUID you can use this command:

xe pool-list params=master | egrep -o "[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}"

To get uuids of all running VMs

xe vm-list is-control-domain=false power-state=running params=uuid | egrep -o "[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}"

so you can create a script to execute the off-line coalescing tool on every VM like this:

#!/bin/bash

MASTER=$(xe pool-list params=master | egrep -o "[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}")
#All VMs
RUNNING_VMS=$(xe vm-list is-control-domain=false params=uuid | egrep -o "[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}")
#All running VMs
#RUNNING_VMS=$(xe vm-list is-control-domain=false power-state=running params=uuid | egrep -o "[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}")
#All halted VMs
#RUNNING_VMS=$(xe vm-list is-control-domain=false power-state=halted  params=uuid | egrep -o "[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}")

for VM in $RUNNING_VMS; do
    echo " "
    echo "=== Starting coalesce leaf process for $VM at $(date) ==="
    echo " "

    xe host-call-plugin host-uuid=$MASTER plugin=coalesce-leaf fn=leaf-coalesce args:vm_uuid=$VM

    echo " "
    echo "=== Coalesce leaf process for $VM ended at $(date) ==="
    echo " "
done

references: http://support.citrix.com/article/CTX123400