User guide

© 2011 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information. Cisco Validated Design Page 126
The following graph represents the total number of sessions per configuration as also noted in the table above.
●
Optimal multiple virtual machine configuration on a single Cisco UCS B200 M2 Blade Server (maximum
scale-out. The maximum number of user sessions supported on a single Cisco UCS B200 M2 Blade Server
with multiple XenApp virtual machines was 180. The optimal virtualized configuration was 4 XenApp virtual
machines each configured with 6vCPU, 16GB RAM and 24GB paging file. To achieve this maximum scale-
out value, each XenApp virtual machine supported 45 users which was less than its maximum scale-up
value of 60 users. The maximum scale-up value is defined as the maximum number of user sessions
supported for a single XenApp virtual machine. This shows that while virtualizing XenApp workloads in real
world environments, the maximum-scale up and scale-out values will not necessarily be the same for
similar configurations.
●
The 6 XenApp virtual machines each configured with 4vCPU, 12GB RAM and 18GB of paging file also
achieved the 180 user sessions, but this configuration is not considered optimal as it requires more
XenApp virtual machines to achieve the same scale-out value. However, customers implementing XenApp
servers in an application based silo might find such configurations optimal for their usage.
●
We also conducted testing for 3 XenApp virtual machines each configured with 8vCPU, 16GB RAM and
18GB of paging file. This configuration yielded the maximum scale-out value of 160 with each virtual
machine supporting ~53 user sessions. While this configuration supports less users, it has the least
number of virtual machines and hence could be considered optimal if reducing OS licensing cost is an
important factor in an environment.
The maximum scale-out tests were conducted with all 24 logical cores utilized, with hyper-threading enabled and
without any vCPU oversubscription. This was based on the general consensus in the industry that that for Server
Based Computing (SBC) environments, scalability is degraded if more vCPUs are assigned then there are CPU
cores.
The following table provides the VSI COPI score for the optimal virtualized configuration consisting of 4 XenApp
virtual machines each configured with 6 vCPU, 16 GB RAM, and 24 GB page file and shows that 100% of all the
180 virtual desktop sessions executed without issue.
120
130
140
150
160
170
180
190
6vCPU*4VMs
4vCPU*6VMs
8vCPU*3VMs
Number of User
Sessions
Citrix XenApp VM Configurations