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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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Figure 6: Login storm I/O performance detail: PS6000XVS hosting 1014 non-persistent desktops
Figure 7 shows the I/O performance measured at the individual disk drives within the storage system at
the same login storm peak I/O point. The data in the table below the chart shows that during peak
load approximately 90% of the array IOPS were served by the SSD drives. During login storm most of
the read I/O is targeted to the replica image. As this happens, the replica image data becomes “hot.”
The PS6000XVS array automatically moves the hot data to the SSD drives. SSD drives provide
significantly better random read I/O performance as compared with the 15K SAS drives. Automatic
movement of the hot data to the SSD tier within the array significantly increased the overall I/O
performance of the array during login storm.
Figure 7: PS6000XVS disk drive IOPS during non-persistent desktop login storm
4.2.2 The steady state task worker activity phase (after the login storm)
After all of the desktop sessions have launched and completed their login phase there was a period of
steady state application activity. Figure 8 shows I/O data as measured by SAN HQ at a peak I/O point
during the steady state phase of the 1014 desktop test. The load created 3600 IOPS (approximately 3.5
IOPS per user desktop) and the array handled the load while staying below 5ms latency on average.