Recently installing Kaspersky on some fileservers , caused the shares to hang which could only be fixed by restarting the Commvault Agent on the server. This is usually down to the way Kaspersky locks the archived files during scan. Heres how to fix : 

->On the Fileserver machines exclude the Antivirus Processes for Kaspersky ( AVP.exe ) 

http://documentation.commvault.com/dell/release_9_0_0/books_online_1/english_us/deployment/upgrade/dm_nas_client.htm

->On the Kaspersky Administration Center create a profile Exclude the Directories and also processes here from being scanned :  

http://documentation.commvault.com/commvault/v10/article?p=white_paper/security/antivirus_exclusions.htm

Lastestly Change the Hierarchical Storage Settings for Kaspersky to the below , however Comm vault say HSM with system with reparse points