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Sizing and Best Practices for Deploying VMware View 4.5

on VMware vSphere 4.1 with Dell EqualLogic Storage

5 Sizing Guidelines for EqualLogic SANs

Client desktop usage in enterprise environments follows typical patterns or phases. For example, at the

beginning of the workday most employees login into their desktops within a relatively small time

frame. During this time “login storms” can be expected. After the login storm, periods of high and low

steady state application activities will occur. For example, high user activity on their workstations

during morning/afternoon hours and low activity during break hours. These phases of activity cause

different I/O patterns and loads in the VDI environment SAN.

5.1 Using Persistent vs. Non-Persistent View Desktops

Persistent desktops use persistent disk storage to store all changes – writes to the OS, temporary

system and application data as well as user data. For non-persistent desktops, no changes to disk

persist between client login sessions. Because of this, when a user logs into a non-persistent desktop,

tasks such as user profile creation, reading and applying GPO data etc. generate significant amounts of

I/O. The results in Section 4 demonstrate that when using non-persistent desktops, there can be

significant spikes in SAN I/O load in large VDI environments during login storm periods.

When considering I/O performance requirements for a VDI SAN you must take into account the

difference in I/O load patterns between persistent and non-persistent desktops. Our test results

confirm that using persistent desktops minimizes the incremental I/O load effect on the VDI SAN

caused by login storm periods. When using persistent desktops we were able to support a higher

number of clients before we reached SAN I/O performance limits.

5.2 Calculating Capacity Requirements for Linked Clone Desktop Pools

There are many variables you need to consider when calculating storage requirements for desktop

pools in VMware View VDI environments. In this section we provide an overview of considerations and

inputs necessary for the calculation. We also provide an example calculation for a 1000 linked-clone

desktop environment. You should consult the VMware View documentation before calculating

requirements for your environment.

Considerations for calculating desktop pool size:

• You should allocate space for two replica images: one image for the linked-clone base image,

and a second image for use by VMware View Composer for recompose activities. The replica

image can be hosted in multiple datastores. Each datastore used for hosting a replica should

allocate space for two replica images.

• The space allocated for each replica image should be the same as the size of the parent

image. (Note: you can place the replica images in a different datastore than the one used for

the desktop VM images.)

• For each desktop VM:

See the “

Storage Sizing for Linked-Clone Desktop Pools

” section in the

VMware

View Online Library

for detailed guidance & formulas:

 http://pubs.vmware.com/view45/ol/