HI All i'm stumped!I have a 2 server enviroment where both servers are mailbox servers. All server's areExchange 2003 Standard Deployment both servers areon physical DL380 G5's. All Datafiles and log files are stored on 4gbps FC SAN. Server 1 has 347GB of data across 2 storage groups and 7 mailbox stores. Server 2 has 335GB of data across 4 storage groups and 16 mailbox stores.Server 2 is having massive disk I/O between 9am and 4pm every day. Messured at avg. disk queue length of 400-1000, average disk sec/write .01-.80, average disk sec/read .0-.80After idenfiying the I/O as coming from Store.exe i focused perfmon at it. For some reason or another the store.exe is accessing a .IFS file 52,000 times every few seconds.... Server 1 does not access any IFS files.Does anyone know whats going on? my only idea is to offline defrag the stores?PS, anti-virus is correctly setup and the arrays holding the stores cant get much faster i belive they are 15x300GB@15k 4gps FC disks.

This should give you a good starting point to troubleshoot. http://almostdailytech.com/2009/05/24/troubleshooting-exchange-2003-performance-issues/Mark Morowczynski|MCT| MCSE 2003:Messaging, Security|MCITP:ES, SA,EA|MCTS:Windows Mobile Admin|Security+|http://almostdailytech.com

run an ExBPA to check if IFS is enabled on Server 2. Also when you say the disks are showing high read and write latencies, is it the disk which holds your database and log files or is it the M: drive for IFS. IFS is particularly used in E2K3 to write directly to the STM file.You can try and disabled IFS and see if that brings the disk latencies down.

The disk that is showing very high I/O is the LUN that has the database files. So then your comments around E2K3 uses the IFS to write to the STM is correct as that is whats going on. Do you have any refrences to a KB for disabling the IFS?

oh also, there is no mapped drive letter to the IFS. The IFS files being slammed beloing to one 32GB Mailbox store. The database files are on F:\Exchsrvr\EX02-IS01\ and the IFS files are in the same directory.

updated -- $#$@#@! mac users! it appears that this WHOLE problem affecting 1200 users is a single mac entrouage 2008 user! When he connects the IFS begins and the I/O goes thru the roof. When he disconnects the IO goes away.......

This is how you actually fix that. http://support.microsoft.com/kb/329067Mark Morowczynski|MCT| MCSE 2003:Messaging, Security|MCITP:ES, SA,EA|MCTS:Windows Mobile Admin|Security+|http://almostdailytech.com

Thanks!