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Sizing and Best Practices for Deploying VMware View 4.5
on VMware vSphere 4.1 with Dell EqualLogic Storage
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The results in Table 4 above show the following:
• For both persistent and non-persistent desktops, we comfortably scaled up to 1014 desktop
VMs using a single PS6000XVS array for storage (test cases A and B above). Non-persistent
desktops created a peak load of 8600 IOPS during the login storm. The PS6000XVS was able
to meet this I/O demand with performance headroom to spare. Also, the PS6000XVS was able
to store all 1014 desktop VM images while maintaining 15% spare capacity in the array, where
each VM image was provisioned with at least 2GB of storage for the linked clone delta disk.
These test results show that the PS6000XVS, using a combination of SSD and 15K SAS drives,
provides a balance between storage performance and capacity that is exceptionally well suited
for supporting VDI environments.
• For test case C (using the PS6000XV with non-persistent desktops), 390 desktops was the
maximum we reached before we exceeded 20ms disk I/O latency (measured from the ESX
host) during the login storm phase.
• For test case D (using the PS6000XV with persistent desktops), 780 desktops was the
maximum we reached before we exceeded 20ms I/O latency (measured from the ESX host)
during the login storm phase.
4.2 Analysis: EqualLogic PS6000XVS SAN hosting non-persistent desktops
In this section we present a detailed analysis of results for Test Case A in Table 4: EqualLogic
PS6000XVS hosting non-persistent desktops. The results for Test Cases B, C and D can also be
analyzed along the same lines using server and storage configuration, EqualLogic SAN Headquarters
(SAN HQ), and vCenter data available from respective simulation runs.
Configuration details for Test Case A at maximum VDI client load:
• 13 ESX server hosts were utilized to scale the simulation up to 1014 concurrent VDI client
sessions.
• The 13 ESX hosts were split into two ESX clusters of 8 hosts and 5 hosts each (VMware View
Composer supports only 8 hosts per ESX cluster).
• The 8 host cluster was provided with 4 SAN volumes on the EqualLogic PS6000XVS. Each
volume was mounted as a VMFS datastore. One of these volumes (32GB) was used for the
linked-clone master replica image. The other 3 volumes (500GB each) were used for storing
the client VM image differential data.
• The second 5 host ESX cluster was provided with 3 volumes: one for the linked clone master
replica (32GB), and two for client VM image differential data (500GB each).
4.2.1 The login storm
Figure 6 below shows I/O data as measured by SAN HQ at the peak I/O point during the login storm
phase of the 1014 desktop test. For non-persistent desktops, each login event causes Windows to
recreate the user profile, read and apply GPO data, and perform other tasks associated with first time
user login. As you can see in Figure 6, the login storm creates significant I/O load on the storage
platform. IOPS were 8,607 while I/O latencies remained well below the 20ms limit during the login
storm peak.