In vSphere 5.1 and later, you can configure the disk space reclamation feature for linked-clone desktop pools. Starting in vSphere 5.1, View creates linked-clone virtual machines in an efficient disk format that allows ESXi hosts to reclaim unused disk space on the linked clones, reducing the total storage space required for linked clones.
About this task
As users interact with their desktops, the linked clones' OS disks grow and can eventually use almost as much disk space as full-clone virtual machines. Disk space reclamation reduces the size of the OS disks without requiring you to refresh or recompose the linked clones. Space can be reclaimed while the virtual machines are powered on and users are interacting with their desktops.
In View Administrator, you cannot directly initiate disk space reclamation for a pool. You determine when View initiates disk space reclamation by specifying the minimum amount of unused disk space that must accumulate on a linked-clone OS disk to trigger the operation. When the unused disk space exceeds the specified threshold, View directs the ESXi host to reclaim space on that OS disk. View applies the threshold to each virtual machine in the pool.
You can use the vdmadmin -M option to initiate disk space reclamation on a particular virtual machine for demonstration or troubleshooting purposes. See the View Administration document.
You can configure disk space reclamation on linked clones when you create a new pool or edit an existing pool. For an existing pool, see "Tasks for Upgrading Pools to Use Space Reclamation" in the View Upgrades document.
If a View Composer is refreshing, recomposing, or rebalancing linked clones, disk space reclamation does not take place on those linked clones.
Disk space reclamation operates only on OS disks in linked clones. The feature does not affect View Composer persistent disks and does not operate on full-clone virtual machines.
Native NFS snapshot technology (VAAI) is not supported in pools that contain virtual machines with space-efficient disks.
Verify that your vCenter Server and ESXi hosts, including all ESXi hosts in a cluster, are version 5.1 with ESXi 5.1 download patch ESXi510-201212001 or later.
Verify that VMware Tools that are provided with vSphere version 5.1 or later are installed on all the linked-clone virtual machines in the pool.
Verify that all the linked-clone virtual machines in the pool are virtual hardware version 9 or later.
Verify that the virtual machines use SCSI controllers. Disk space reclamation is not supported on virtual machines with IDE controllers.
For Windows 8 or 8.1 virtual machines, verify that the machines are running in vSphere 5.5 or later. Disk space reclamation is supported on Windows 8 or 8.1 virtual machines in vSphere 5.5 or later.
For Windows 7 or Windows XP virtual machines, verify that the machines are running in vSphere 5.1 or later.
Verify that disk space reclamation is enabled in vCenter Server. This option ensures that the virtual machines in the pool are created in the efficient disk format that is required to reclaim disk space. See the View Administration document.
- In View Administrator, display the Advanced Storage page.
New desktop pool
Start the Add Desktop Pool wizard to begin creating an automated desktop pool. Follow the wizard configuration prompts until you reach the Advanced Storage page.
Existing desktop pool
Select the existing pool, click Edit, and click the Advanced Storage tab. To upgrade a pool to support space reclamation, see "Upgrade Desktop Pools for Space Reclamation" in the View Upgrades document.
- Select the Reclaim VM disk space check box.
- In the Initiate reclamation when unused space on VM exceeds text box, type the minimum amount of unused disk space, in gigabytes, that must accumulate on a linked-clone OS disk before ESXi starts reclaiming space on that disk.
For example: 2 GB.
The default value is 1 GB.
What to do next
You can configure blackout days and times during which disk space reclamation and regeneration for View Storage Accelerator do not take place. See Set Blackout Times for ESXi Operations on View Virtual Machines.
In View Administrator, you can selectand select a machine to display the last time space reclamation occurred and the last amount of space reclaimed on the machine.