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BP1018 Sizing and Best Practices for Citrix XenDesktop with Dell EqualLogic Storage 33

For more information regarding the different Provisioning Services vDisk modes, please refer to the

following link: http://support.citrix.com/proddocs/topic/provisioning-56/pvs-technology-overview-

vDisk-modes.html

6.1.2 Write cache capacity requirements

The write cache is a temporary disk on each virtual desktop which contains the modified blocks from

each user session. The write cache file is deleted during each reboot cycle.

The options for storing write cache are:

• Cache on PVS

• Cache on target device (virtual desktop) local RAM

• Cache on target device (virtual desktop) local Hard Drive

For more information regarding the different write cache destinations for standard vDisk images,

please refer to the following link:

http://support.citrix.com/proddocs/topic/provisioning-56/pvs-technology-overview-write-cache-

intro.html

The size of the write cache depends on several factors such as type of applications used, user

workload, and frequency of reboots. It is highly recommended to run a pre-deployment environment

to determine the exact write cache usage. For the applications we tested, we found that 2 GB of write

cache was sufficient for the workload under test.

6.2 Storage performance considerations

The key results from our tests from section 5 are summarized in the table below.

Table 6 Test results for one array and two array configurations

Test configuration 1 x EqualLogic PS6010XVS 2 x EqualLogic PS6010XVS

Total number of desktops

630 1270

Number of datastores used to

store virtual desktop write cache

Number of virtual desktops per

datastore for write cache

~160

Number of blade PowerEdge

M610 servers used to host virtual

desktops

8 16

Number of virtual desktops per

ESXi server

Average latency

< ~ 10ms

< ~10ms

Peak IOPS during login storm

6846 12400