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BP1018 Sizing and Best Practices for Citrix XenDesktop with Dell EqualLogic Storage 25
- During login, there is usually extra processing at the DDC to authenticate and allocate a
specific user to one of the available pre-booted desktops.
- There is also increased processing on the PVS layer because there is an increased amount of
activity related to reading the master disk image and streaming it to all virtual desktops.
Memory utilization:
The ESXi servers hosting provisioning servers and DDCs had sufficient memory resources available and
we did not observe any memory ballooning or swapping at any point during the test.
VDI Network utilization:
We dedicated two virtual NICs (vmnic3 and vmnic5) for handling VDI streaming traffic. These two
virtual NICs were teamed together to create a vSwitch and presented to DDC as gigabit adapter using
the VMXNET3 driver. The peak network utilization did not go beyond 40 MB at any point of time
during the test.
5.4.5 User experience: Application performance
The virtual desktop user experience and desktop performance was measured using Stratusphere UX.
Stratusphere UX generates a magic quadrant style scatter plot which shows the performance of virtual
desktops based on machine and I/O experience. All 630 VMs were represented as GOOD performing
desktops in the Stratusphere UX scatter plot as shown in Appendix D .
5.4.6 Write cache utilization on virtual desktops
In our tests, we configured 2 GB as the write cache on each virtual desktop. The “Cache on Device
Hard Drive” option was used to mount the write cache. We measured the write cache space utilization
individually on specific virtual desktops and it never reached 75% even after running the workload on
630 virtual desktops for more than ten hours.
5.5 Task worker – 20% Pre-boot
This test was designed in the same way as the “100% Pre-boot” scenario except that only 20% of the
total desktops were pre-booted. In this test, only 126 virtual desktops (20% of the 630) were pre-
booted and the remaining desktops got booted when additional users started logging into the
desktops.
5.5.1 Storage layer: EqualLogic array performance
The maximum IOPS on the storage array during login storm and steady state was almost the same as
the 100% Pre-boot task worker test, but the login time increased significantly.