You may have noticed over the last half of the Fall ’09 semester that your account may have taken an unusual amount of time to log in at times. After extensive troubleshooting by our System Administrators and Microsoft, we believe we have identified a significant factor, if not the cause, of the performance problems we have been experiencing. The performance issues appear to be related to Outlook PST files being accessed directly from the S drives (or T drive); closing the connections to only PST files appears to return response times to normal levels.
PST files are not supported on network shares; this is something we have been aware of but never addressed as it did not seem to cause us an issue and seemed a good solution for keeping exchange mailboxes small. There are several articles detailing why they should not be stored on the network: http://blogs.technet.com/askperf/archive/2007/01/21/network-stored-pst-files-don-t-do-it.aspx and http://support.microsoft.com/kb/297019/en-us probably provide the best overview.
We cannot be 100% certain that the PST files are the only cause, but to further investigate (and be in a supported configuration) we must remove all PST, OST and PAB files from s: drives and the t: drive. The first part of our plan is as follows:
Over the Christmas break, we will:
- Implement file screening to prevent storing .pst, .ost and .pab files on the s: and t: drives; any users that currently have these file types stored will still be able to access, modify and delete the files, but not rename, create or restore. If you try to move, copy, create, or rename a PST file you will see the following errors.
- Disable Outlook Archive; this will prevent the automatic creation of PST files.
We will attempt to make this change as painless as possible and work with you on any quota issues that you run into with Exchange to accommodate.