Hi We're running Exchange 2007 on an HP SAN - SCC model, Active/Active/Passive. Per EVS, we have five storage groups, each with one mailbox store. We are going to be adding another two SG's. The difference is that whereas now each SG's has dedicated disks, the new SG's will share their disks with other apps on the SAN. The new SG's will be for lower use users - i.e. ones that access Outlook less often. One question - if we start seeing delays on the new SG's, can this affect the existing SG 1-5's? I guess the question is - if we start seeing disk related bottlenecks for the new SG's, can this cause delays for the existing SG's? I was thinking that if we did have disk delays, this could increase RPC latency for the entire server?

No because you've isolated the SG's into their own disk group (lun)James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Hello James Sure....but let's say there was a severe delay on SG7-DB1 (one of the new ones). Wouldn't this push up RPC Latency for the entire server?

Hi, Since you are dedicating storage drives to the specific database and logs you should be all right. You should still monitor the Exchange server for bottlenecks but don't think you you see any negative results for the users on the primary storage groups. Also remember that Exchange 2007 isn't as demanding on the storage system as Exchange 2003 was. /MartinExchange is a passion not just a collaboration software.

Yes you can expect the value to go up since it's measuring all RPC operations for all mailbox users. However this doesn't mean it's actually slowing down the other users in the better tier disk groups.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Hi, I think the new disk will not affect the old storage group because resolve engine will find the address where the mailbox located and initial a routing table for the message. If the mailbox is in old storage group, when process a RPC Request the server will not access the new storage group. In addition, read this article for performance troubleshooting http://blogs.technet.com/b/exchange/archive/2005/09/28/411674.aspx Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.