Exchange 2007 memory

iaind · 11 Mar 2009 at 13:23

I recently installed a new Exchange 07 server and migrated our 25gb of mailboxes onto it from the old Exchange 03 box. Its running on 2003 x64 R2 on a DL380G4, 3.0Ghz Xeon and 3gb RAM. There's nothing else on it other than Sophos Puremessage and DoubleTake

I know Exchange is meant to use as much RAM as possible to optimise IO, but every few days, the store.exe process uses almost all the available memory and the server grinds to a halt. When it happens we regularly get "Outlook is trying to retrieve data..." messages and long delays in Outlook generally. Normally performance is superb and a restart of the IS process fixes it.

Never seen anything like this in 03, I know its not a huge amount of RAM but it should be enough, surely?

Has anyone else seen problems like this? Would limiting the memory usage to, say, 2gb solve the problem?

madman045 · 11 Mar 2009 at 13:29

I would have thought you might have at least 4GB, if not 8GB of ram in a X64/Exchange 2007 box?

How many users do you have and what's their usage like?

iaind · 11 Mar 2009 at 13:30

I did want to put more in it but its all I had spare (6 x 512), and its only a stopgap measure until our new ESX servers arrive.
About 90 users, fairly light usage. The old 03 box was fine with the same usage on a DL380 G3 (2.4Ghz) with 2gb RAM.

madman045 · 11 Mar 2009 at 13:33

http://technet.microsoft.com/en-us/library/bb738124.aspx

Yes but you have one server with multiple roles running, Exchange 2007 has a different structure to a single exchange 2003 system, hence they have separate memory requirements

In your case, probably 8GB would be a minimum

iaind · 11 Mar 2009 at 13:37

Thought that might be the case - its frustrating as while I understand it's a different beast to Exchange 03, the box isnt actually being used for anything more than the old one.
Will just schedule a nightly restart of the IS service in the mean time and give the virtual box 8gb when I build it

Seaniboy · 11 Mar 2009 at 13:38

This is the nature of exchange 2007, it will just comsume pretty much as much memory you can throw at it for caching. Strange that your getting "Outlook is trying to retrieve data..."

How many client's do you have? Is this box dedicated to exchange?

iaind · 11 Mar 2009 at 13:43

Seaniboy said:
This is the nature of exchange 2007, it will just comsume pretty much as much memory you can throw at it for caching. Strange that your getting "Outlook is trying to retrieve data..."

How many client's do you have? Is this box dedicated to exchange?

Thats what I expected, which is why I was suprised when it started grinding to a halt when it got to a certain usage. It's also strange that it performs flawlessly until this happens.

I may be wrong and the problem might be elsewhere, but normally when I look there's less than 50mb free RAM and restarting the store gets it going again.

It is dedicated to exchange with just the AV and replication software installed alongside. There's about 90 mailboxes but its rare for everyone to be using it at once - for example at this moment we have 52 active users

Seaniboy · 11 Mar 2009 at 13:56

Worth a look - http://technet.microsoft.com/en-us/library/bb738124.aspx

Which AV are u you using? Also what disk configuration have you setup?

Your mailbox and usage count is similar to mine, we have 4GB in a dual quad core machine and it is consuming about 95+% of the physical memory but clients do not have any problems. Trying to use the box from the console/rdp can be quite painful though.

iaind · 11 Mar 2009 at 14:04

Seaniboy said:
Worth a look - http://technet.microsoft.com/en-us/library/bb738124.aspx

Which AV are u you using? Also what disk configuration have you setup?

Your mailbox and usage count is similar to mine, we have 4GB in a dual quad core machine and it is consuming about 95+% of the physical memory but clients do not have any problems. Trying to use the box from the console/rdp can be quite painful though.

2 x 36gb 15k mirror for OS and logs, 4 x 36gb 10k RAID5 for the data. Again, not optimal but we're not hitting any bottlenecks with it.

AV is Sophos Puremessage, which isnt great to be honest.

One thing I did notice was someone (not me!) had set the pagefile to 2gb fixed, so I changed it to system managed and will schedule a reboot tonight.

I did think if the server was underspecced we'd get consistent sluggish performance, but this flies 99% of the time and just seems to hit a wall

Seaniboy · 11 Mar 2009 at 14:12

The PF could be your problem. Currently have pagefile set at Initial 2GB - Max 6GB.

Let us know how you get on.

iaind · 11 Mar 2009 at 14:15

I would be suprised if that doesnt help at least, not sure which numpty set it like that!

brainchylde · 11 Mar 2009 at 23:59

Is your antivirus configured correctly? Microsoft recommend you exclude a number of files/folders from Virus scanning for Exchange - you can end up in quite a pickle if you don't do this (corruption etc.)

iaind · 12 Mar 2009 at 07:46

Yep definitely, when you install sophos puremessage for store scanning, it also installs the regular AV and excludes all the correct paths.
I'm not excluding Sophos generally being crap as the source of the problem, though, as it wouldnt be the first time. It caused our file server to lock up for a minute every time someone saved an encrypted file....

brainchylde · 12 Mar 2009 at 23:08

Just in case have a read through this -

http://technet.microsoft.com/en-us/library/bb332342.aspx

to make sure your antivirus is configured as MS recommend. The only reason I say to double check is I notice you are moving from Ex03 and the antivirus exclusions are a little more detailed in 07.

Let us know how you get on.

RSR · 13 Mar 2009 at 10:09

Ive had a simlar problem to this running Exchange 2003.

However my setup was a little difference. I was running a DL380 G4 using QLogic iSCSI cards this was linked to a NetApp SAN via iSCSI.

Our DBs total just over 1.1 TB, but there is heavy usage on public folders. I know exchange was never designed for this in the first place.

After trouble shooting for ages. It turned out our problem was linked to the Qlogic cards not being able to provide enough I/O and also the latence was also very high. It was oftern around 50MS + which is a no go for Exchange.

If you havin't already run a Perfmon on Avg. Disk Queue Length. Generally up to 2 per spindle (Hard Disk Device) is acceptable. This should give you a good idea of I/Os

Also a response time of 20MS or lower is recommended.

Andy

RSR · 13 Mar 2009 at 10:12

Seaniboy said:
Worth a look - http://technet.microsoft.com/en-us/library/bb738124.aspx

Which AV are u you using? Also what disk configuration have you setup?

Your mailbox and usage count is similar to mine, we have 4GB in a dual quad core machine and it is consuming about 95+% of the physical memory but clients do not have any problems. Trying to use the box from the console/rdp can be quite painful though.

Disk Queue Lenth can cause this. Ive seen store.exe use 95% of all the system memory due to high latency.

Andy

RSR · 13 Mar 2009 at 10:13

Also have you removed the AV as a test from the server? It maybe worth doing as you can rule that out then.

Andy

cybergeek · 15 Mar 2009 at 01:32

I just did a SBS install this week and it wouldn't install until I upgraded the RAM to 4GB

iaind · 15 Mar 2009 at 01:49

?? Ok...

That's because the minimum requirement for SBS 08 is 4gb and is probably enforced during setup. The minimum for Exchange 07 is 2gb.

cybergeek · 15 Mar 2009 at 01:53

iaind said:
?? Ok...

That's because the minimum requirement for SBS 08 is 4gb and is probably enforced during setup. The minimum for Exchange 07 is 2gb.

You are probably right there, I've not done a Ex07 stand-alone install in quite a while.