During the boot storms, data was collected using Perfmon and Task Manager on the WSM server. The
resources used during the boot storms were recorded in Figure 64. These were the burst values.
Average usage of each of these resources was much less.
Figure 64: WSM Server Resources Used (Burst values)
# of clients
CPU usage (%)
Disk Usage (MBps)
Network Usage (Mbps)
One important data point is that the boot storms present the maximum load on the server from a resource
perspective. The times and system resources needed are dependent on the size of the VDISK image. For
example, if the vdisk image is in and around 25GB, the performance and usage can be expected as seen
above. If the vdisk size increases significantly like 35GB, 40GB etc.., the performance metrics as in the
number of clients supported will be smaller. The general rule is as follows,
Number of theoretical maximum clients = 70-75 %( 2000/vdisk size in GB)
Vdisk size = 25GB
70 %(2000/25) ~ 50 users
Vdisk size = 35GB
70%(2000/25) ~ 40 users
Please note that the above formula is a general guideline. Other parameters like network limitations will
play a factor in optimal performance tuning.
The next phase of testing will include resource utilization during user activity. Application loading and
usage will be recorded and presented in a future version.
The network utilization was also recorded from the task manager and recorded for 30 users in Figure 65.
Each tick mark in the time domain represents 6 seconds. In this figure, you can see the peaks for the
various phases of the booting process. The first set of peaks represents the traffic sent from WSM to tell
the streaming clients to shut down and the traffic sent from the clients to close out the open files and
disconnect the remotely mounted drives. There is about a 30 second pause while the clients are
executing their BIOS commands and waiting for an answer from the DHCP server. The second phase is
when the client devices load the pre-booter via PXE boot. The Third Phase is the OS image loading from
the WSM server. The last set of peaks show network traffic for the auto login using a user roaming
profiles and remote file server mounts for the home directories.
Figure 65: Network Usage during 30 user Boot Storm