Thursday, February 7, 2008

Performance Testing your Disk Subsystem for Exchange

Hello All,

So, I've spent some time (a few months) researching a major upgrade to provide a client higher performance for Exchange, near real time disaster recovery, and ability to quickly restore large Exchange databases (50-100GB). I just want to touch on the higher performance aspect of my research.

One of the major issues with Exchange 2003, is when users have large mailboxes (think 5-15GB (yes, GB) mailboxes, and they attempt to sort a column in Outlook that has thousands of items, Exchange has to work very hard to accommodate this request. This will stress an Exchange subsystem to handle this. So, in my quest to recommend a higher performing disk subsystem (they were using direct attached storage [aka SCSI], I proposed a scaled storage area network solution). So, one of my first tasks to determine how to get the best performance out of the SAN will be to use the following 2 Microsoft tools for performance testing of Exchange when I attempt to configure the SAN disk subsystem for RAID 1, 5, and 10. Also, these tools can highlight network related issues, so make sure to examine your networking especially if you are running on a SAN (e.g. MPIO, jumbo frames, teaming, etc). These can make a very big difference in performance as well.

1) Microsoft Exchange Server Jetstress
*** Summary ***Microsoft Exchange Server is a disk-intensive application that requires a fast, reliable disk subsystem to function correctly. Jetstress is a tool that helps administrators verify the performance and stability of the disk subsystem before putting their Exchange server in a production environment.

Jetstress works with Exchange Server Database Storage Engine to simulate the Exchange database and log disk I/O load. If you run Jetstress and have missing libraries, you will receive a message that states that you must copy any missing DLL files from Exchange 2000/2003/2007 installation CD/DVDs to the Jetstress installation directory and rerun Jetstress.

2) Microsoft Exchange LoadSim

*** Summary ***
Use Microsoft Exchange Server 2003 Load Simulator (LoadSim) as a benchmarking tool to simulate the performance load of MAPI clients. LoadSim allows you to test how a server running Exchange 2003 responds to e-mail loads. To simulate the delivery of these messaging requests, you run LoadSim tests on client computers. These tests send multiple messaging requests to the Exchange server, thereby causing a mail load. LoadSim is a useful tool for administrators who are sizing servers and validating a deployment plan. Specifically, LoadSim helps you determine if each of your servers can handle the load to which they are intended to carry. Another use for LoadSim is to help validate the overall solution.