Endpoint Protection

Every morning at approx 9am our HP San locks up for about 5 mins. We've ruled out everything on the network & the cause appers to be the main AV server (If its swutched off we get no problem ). We have approx 380 servers on the network & 4,000 client PC's. The servers are a mix of virtual & physical.

I've tried troubleshooting the issue but can't seem to get anywhere with it - anyone got any ideas ??

Things tried

Unistalling reporting services
Disabling autoprotect on affected server
Amending time of definition downloads
Stopping 'run quick scan' after loading new definitions

Thanks Garbo

Are you sure it is related to Symantec Software. When you say "Switched off", do you mean shutting down the Symantec services?
What errors are you seeing on the HP SAN? Are you seeing any errors on the main AV server?

Thomas

 This would be a rare case, almost slim to none, that AV software is brining down a SAN.  Perhaps a NAS, but not a SAN.

That said, verify that your Parent server with it's LUN's attached, are isolated so that the LUN is zoned or mapped to only that AV server, and nothing else. 

I'd also make sure that you dont have all of your 380 servers kicking off scheduled scans at the same time, that is a great way to bring your SAN down with excessive disk IO.