Exchange 2000 Enterprise Max RAM Support

[IS300]

I am curious as to what is the maximum amount of RAM that Exchange 2000 Enterprise can support. We are running Windows 2000 Server with 2GB of RAM in it. Is it fully optimizing this? I've heard that if you have Advanced Server you can use the /3GB switch to increase the amount of RAM exchange will use, assuming you have more than 1 GB.

Is that correct?

 

[Zelandakh]

Exchange 2000 Enterprise can support 4GB on Windows Standard and rather more on Windows Enterprise.

The /3GB should be used above 1GB, yes.

 

[pmandryk]

Yes, it can support it, but we have found quite a lot of problems in the Event logs with memory allocation errors and Exchange wanting to take all of your server's memory. The /3GB switch is only to be used with W2K Advanced server, not Standard. We found that after 2GB of RAM very weird errors kept popping up and our Exchange box would crap out after two days, claiming that there were Virtual Memory Fragmentation errors. Only a stop/start of the services would fix these. Needless to say, management wasn't too happy. We went to Ex2K3 on W2K3 Advanced SP1, without problems.

 

[58sniper]

We haven't seen problems with the /3GB and /userva switches when using Standard with 2GB of RAM or more. Dozens of servers staying stable...

Pat Richard, MCSE(2) MCSA:Messaging, CNA(2)

 

[pmandryk]

Good to hear, Pat. I, too, used the /3GB switch on my Standard servers and it didn't do anything, good or bad. However, when I phoned a friend at Microsoft, he said that if there were problems, and MS knew that the switch was in there, they might not support it, or at the very least, give you a hard time about it.

Phil Mandryk MCSE, CNE

 

[netometer]

Exchange can not utilize effectively more than 3 GB system memory – it is the way this application is written.
Therefore it is useless to install more than 3 GB on the server which is running Exchange unless you are using this server for other purposes too.

Dean

Dean

http://www.netometer.net/help/helpdesk.html

 

[Zelandakh]

Sort of agree with you. "Other purposes" I would include Windows which can have another 1GB before you start to get into wasting time territory.

 

[xmsre]

1. 4GB of RAM.

http://support.microsoft.com/kb/328882/en-us

2. /USERVA applies to Windows 2003, not Windows 2000. For Windows 2000, you'll want to set systempages to 30000 to get the same effect.

http://support.microsoft.com/kb/313707/en-us

 

[netometer]

Actually, I was wrong. It is 4 GB which Exchange can effectively utilize. Here is the detailed explanation by Evan Dodds – a technical lead in the MS Exchange admin group:

http://support.microsoft.com/default.aspx?scid=/servicedesks/webcasts/en/transcripts/wct061604.asp

• “Our next question is: I'm running Windows Server 2003 Enterprise Edition with Exchange 2003, and I have 5 GB of RAM in my server. Is this a waste, or are there any switches besides the /3gb /Userva=3030 switch that can help utilize this extra RAM? I only see references to machines that have 4 GB of RAM and no more.

Evan: Because of the way Exchange uses memory, there is generally no benefit to having more than 4 GB of RAM inside your server. If you're running other applications on the server apart from Exchange, you may find that there is some benefit to doing it. But if you have a dedicated Exchange server, generally 4 GB of RAM will get you the best performance. Do you know anything additional that he could do, Nino?

Nino: No. I'm not aware of anything else. I believe that's correct. It's really the limitation of how Exchange is designed. It's just that the design of the product will not let us address more. At this point, 4 GB is really all that you need. However, as Evan mentioned, some other applications that are running on the server, if there are other applications, might benefit from it.”


• By other purposes I meant running other applications on the Exchange server.
• I’ve never met the term “wasting time territory” and I would appreciate if Zelandakh elaborates on it – it sounds interesting.

Dean

Dean

http://www.netometer.net/help/helpdesk.html

 

[Zelandakh]

Sorry, let me elaborate:

Standard = 4GB. Anything more and you are wasting time and money.
Enterprise = can go more than 4GB. Exchange will only use 3GB on E11. So you net 1GB for other things. If you have a lot of stuff like IIS, DNS, AD etc then perhaps another 1GB could be beneficial but otherwise 4GB is more than enough and you then only need Standard.

And if Nino Bilic speaks, it is the truth...

 

[xmsre]

I'm running Windows Server 2003 Enterprise Edition with Exchange 2003, and I have 5 GB of RAM in my server. Is this a waste, or are there any switches besides the /3gb /Userva=3030 switch that can help utilize this extra RAM? I only see references to machines that have 4 GB of RAM and no more."


5GB is a problem. Over 4GB will case the PAE kernal to load, which is something to don't want. Also, I don't see a reference to the /noexecute=optout switch in your boot.ini. In W2K3 SP1, DEP loads the PAE kernal anyway unless you specify this option. So,

/3GB /USERVA=3030 /NoExecute=optout /NOPAE