Monday, May 09, 2005

Exchange 2003, Windows 2003 SP1, and PAE

Windows 2003 Service Pack 1 introduced a new feature called Data Execution Protection (DEP). The DEP feature essentially protects the operating system from applications that might run applications with buffer overruns. Some folks are finding that when they run the Exchange Best Practices Analyzer, it is reporting that PAE is enabled.

Exchange 2000/2003 is not compatible with DEP nor PAE. On some hardware, PAE (Physical Address Extensions) is automatically enabled. PAE allows the Windows Server operating system to use memory above 4GB. This can benefit some types of application servers such as SQL Server or Terminal Servers. This does not benefit an Exchange server.

In order to make sure that your Windows 2003 SP1 server is not using PAE or DEP, you should include the following lines in your BOOT.INI file:

/NOPAE /EXECUTE

The above options carry the Paul Bowden seal of approval. The /EXECUTE switch is not well documented, but it can be found in the Windows Internals 4th Edition Book. Of course, if the server has more than 1GB of physical memory, the BOOT.INI should include these options:

/3GB /USERVA=3030 /NOPAE /EXECUTE

As many administrators have found out, the /NOPAE /NOEXECUTE=OptOut and the /NOPAE /NOEXECUTE=AlwaysOff options do NOT always turn off DEP and PAE. This may depend on the hardware you are using, so use the /3GB /USERVA=3030 /NOPAE /EXECUTE switches in your BOOT.INI file.

References /Bibliography:

KB 283037:Large memory support is available in Windows 2000 and Windows Server 2003

KB 817566:
When starting with both the /PAE and the /3GB switches, the system may not start

KB 823440: Use of the /3GB switch in Exchange Server 2003 on a Windows Server 2003-based system

KB 328882: Exchange Memory Use and the /3GB Switch

KB 291988: A description of the 4 GB RAM Tuning feature and the Physical Address Extension switch

Newsgroup discussion and comments from Paul Bowden

KB 827281: CPU and memory scalability for Exchange Server 2003 and for Exchange 2000 Server

3 Comments:

At 10:27 PM, Blogger Jim McBee said...

This has been updated. See the Exchange Team's blog for an official discussion on this.

http://blogs.technet.com/exchange/archive/2005/07/05/407330.aspx

 
At 5:46 AM, Blogger Steven said...

I’m trying to find out about Unified Communication for a project but there doesn’t seem to be much information available. Is it the same as VoIP, and if not how is it different?

 
At 3:38 AM, Blogger matthew said...

very nice post
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