XenDesktop and Provisioning Services Anti Virus Best Practices
If you do not configure your antivirus software properly, the performance of the Target Device and Provisioning Services Server can be greatly impacted. Below is a list of symptoms consistent with an Antivirus client that needs to be tuned:
• The Target Device seems sluggish or generally slower than normal after installing or upgrading your antivirus client.
• You notice prolonged high CPU use.
• You see a significant change in the write cache Disk I/O Performance. For example, if the percentage of disk write time or disk write queue length increase significantly.
• The Target Device software indicates excessive retries in its console.
Regardless of whether you are currently experiencing any of these symptoms, you should follow the steps outlined in the Resolution section below.
In general, most antivirus products defaults are configured to scan all files and processes on a disk, and just like an operating system that runs locally to its hardware, usually all I/O operations are subject to real time scanning, as well. If an antivirus program scans the continuously active data stream that delivers the operating system, this impedes the normal operation of Provisioning Services by causing performance delays. When a vDisk is running in standard mode and needs to be restarted, it downloads all of its previously loaded virus definitions. This is a common scenario and can cause serious degradation when rebooted several at a time, often causing a congested network pipe while the operation persists. In extreme cases, the Provisioning Services Target Device and Server can become sluggish and consume more resources than necessary. This can potentially lead to a negative impact on the overall performance of the device(s) being streamed.