Hi all We have an issue with our exchange 2003 server which has SAN attached storage for its databases (2 x 200gb databases), whereby i am seeing high disk queues for one of the drives with a database on, this i beleive is leading to some performance issues. Our SAN guys say that the infrastructure is all good and under very low load, with the specific LUN showing 600IOPs max only, so what i dont understand is why i would be getting disk queues on our exchange server when the SAN seems ok? Would it be due to the poor handling of IO that Exch 2003 has? maybe a limitation of ESE? We have it on a RAID 5 group with a LUN with no other contention from other applications / servers. Cheers Stew

Hi, It can we due to many reasons, kindly confirm which SAN it is IBM or EMC, what the free space, have you tried increasing the LUN size & after that also if the same issue occurred or not, is the SAN drivers al up to date, do the queue length increase on a particular time or it remains up all the time. Ripu Daman Mina | MCSE 2003 & MCSA Messaging

Are your also face complian for MAPI connection and mail flow issue for user hosted in same DB ?. If you are seeing queue length contineu then there is some issue going on from storage side. You need to check Log at storage controller. Also event log in exchange server will give you idea if any problem from server side.Anil

yeah i think its down to the storage size too, hitting some higher IOPS which the RG cant handle too well due to the randomised IO of the exchange database.

What makes you think you are having performance issues? BTW, according to: http://technet.microsoft.com/en-us/library/aa997558(EXCHG.65).aspx Ruling Out Disk-Bound Problems The average should be less than the number of spindles of the disk. If a SAN is being used, ignore this counter and concentrate on the latency counters: PhysicalDisk\Average Disk sec/Read and PhysicalDisk\Average Disk sec/Write

thanks for the link andy, perfect. :)