After Exchange Server's databases and transaction logs, the resources that consume the highest number of disk I/Os are queues. Exchange Server uses two different queues: the MTA queue and the SMTP
MTA queues are used as a temporary message repository for messages received from Exchange 5.5 servers, or for messages that arrive via an X.400 connection. MTA queues are also used to temporarily store messages that arrive while a mailbox is being moved. SMTP queues handle inbound and outbound SMTP messages.
You will have to look at your individual server's needs to determine the appropriate placement of the SMTP queue and MTA queue. In most Exchange Server 2003 deployments though, the MTA queue is barely even used, so it's usually acceptable to store the MTA queue on the same volume as the SMTP queue.
It is not OK to put your MTA queue on the same volume as your SMTP queue if your MTA queue is moderately to heavily used. You might also want to avoid sharing a volume between the two queues if the Exchange server receives so much SMTP mail that it has trouble keeping up with the demand.
Whether or not you decide to group the SMTP and MTA queues together, they need to be placed on a dedicated partition. Microsoft recommends a SAN-based RAID 0+1 volume.
Some administrators have been known to cut corners and not use a dedicated volume for the SMTP and MTA queues. If you decide that you don't want to use a dedicated volume for Exchange Server's queues, then it is extremely important that you don't place the queues on the same volume as the Exchange databases or transaction logs.
To move the SMTP queues:
- Open Exchange System Manager and navigate to Administrative Groups -> your administrative group -> Servers -> your server -> Protocols -> SMTP -> Default SMTP Virtual Server.
- Right click on the Default SMTP Virtual Server and select Properties.
- Go to the Messages tab to set the location for the SMTP queue.
Figure A: Control SMTP location from Default SMTP Virtual Server properties.
To move the MTA queue:
- Go to Exchange System Manager -> Administrative Groups -> your administrative group -> Servers -> your server -> Protocols -> X.400.
- Right click on the X.400 container and select Properties. You can set the location for the MTA queue on this page.
Figure B: The MTA queue's location is set through the X.400 properties sheet.
BEST PRACTICES GUIDE: EXCHANGE SERVER DISK PERFORMANCE
Part 1: Disk performance best practices for Exchange Server databases
Part 2: Disk performance best practices for Exchange Server transaction logs
Part 3: Disk performance best practices for MTA and SMTP queues
Part 4: Disk performance best practices for Windows pagefiles
Part 5: Disk performance best practices for Exchange Server indexing
Part 6: Disk performance best practices for deleted Exchange database pages
Part 7: Microsoft recommendations for structuring an Exchange disk subsystem
Part 8: Related links on Exchange Server performance management
|ABOUT THE AUTHOR:|
Brien M. Posey, MCSE|
Brien M. Posey, MCSE, is a Microsoft Most Valuable Professional for his work with Exchange Server, and has previously received Microsoft's MVP award for Windows Server and Internet Information Server (IIS). Brien has served as CIO for a nationwide chain of hospitals and was once responsible for the Department of Information Management at Fort Knox. As a freelance technical writer, Brien has written for Microsoft, TechTarget, CNET, ZDNet, MSD2D, Relevant Technologies and other technology companies. You can visit Brien's personal Web site at http://www.brienposey.com.
This was first published in July 2006