Setting Up Desktop and Application Pools in View

Table 15‑4. Storage Sizing Formulas for Linked-Clone Disks When You Edit a Pool or Store Replicas on a
Separate Datastore
Data Type
Selected Free
Space (GB)
Min Recommended
(GB) 50% Utilization (GB)
Max Recommended
(GB)
OS disks Free space on the
selected datastores
Number of new VMs
* (2 * memory of VM)
Number of new VMs
* (50% of replica disk
+ memory of VM)
Number of new VMs *
(100% of replica disk +
memory of VM)
Persistent disks Free space on the
selected datastores
Number of new VMs
* 20% of persistent
disk
Number of new VMs
* 50% of persistent
disk
Number of new VMs *
100% of persistent
disk
Example of a Storage Sizing Estimate When You Edit a Pool or Store Replicas on
a Separate Datastore
In this example, the parent virtual machine is configured with 1GB of memory. The parent virtual machine's
disk size is 10GB. A linked-clone pool is created with 10 machines. Persistent disks are configured as
2048MB in size.
The OS disks are configured on a datastore that currently has 184.23GB of available space. The persistent
disks are configured on a different datastore with 28.56GB of available space.
Table 15-5 shows how the sizing formulas calculate estimated storage requirements for the sample linked-
clone pool.
Table 15‑5. Example of a Sizing Estimate for Linked-Clone Disks When You Edit a Pool or Store Replicas
on a Separate Datastore
Data Type
Selected Free
Space (GB)
Min Recommended
(GB) 50% Utilization (GB)
Max Recommended
(GB)
OS disks 184.23 10 * (2*1GB) =
20.00
10 * (50% of 10GB +
1GB) =
60.00
10 * (100% of 10GB +
1GB) =
110.00
Persistent disks 28.56 10 * (20% of 2GB) =
4.00
10 * (50% of 2GB) =
10.00
10 * (100% of 2GB) =
20.00
Storage Overcommit for Linked-Clone Virtual Machines
With the storage overcommit feature, you can reduce storage costs by placing more linked-clone virtual
machines on a datastore than is possible with full virtual machines. The linked clones can use a logical
storage space several times greater than the physical capacity of the datastore.
This feature helps you choose a storage level that lets you overcommit the datastore's capacity and sets a
limit on the number of linked clones that View creates. You can avoid either wasting storage by
provisioning too conservatively or risking that the linked clones will run out of disk space and cause their
desktop applications to fail.
For example, you can create at most ten full virtual machines on a 100GB datastore, if each virtual machine
is 10GB. When you create linked clones from a 10GB parent virtual machine, each clone is a fraction of that
size.
If you set a conservative overcommit level, View allows the clones to use four times the physical size of the
datastore, measuring each clone as if it were the size of the parent virtual machine. On a 100GB datastore,
with a 10GB parent, View provisions approximately 40 linked clones. View does not provision more clones,
even if the datastore has free space. This limit keeps a growth buffer for the existing clones.
Table 15-6 shows the storage overcommit levels you can set.
Chapter 15 Reducing and Managing Storage Requirements
VMware, Inc. 207