I'm not a big fan of such a generalization, but I think Michael is on target with his recommendation. He arrived there with a general rule of thumb, but there are clear reasons for adding memory.
First off, how large is your "small" domain? See http://technet.microsoft.com/en-us/library/aa996719.aspx for the recommended specs. While 2GB is the minimum, the recommendation is to add an additional 5 MB of RAM per mailbox - so if you have 400 mailboxes, then 4GB is about right.
But you're not just running Exchange here - the ForeFront usage puts you way over those minimum requirements. You could manage this better, perhaps, if you don't need to run through multiple scanning engines. Reducing that number would let you reduce the memory required as well.
But memory is cheap these days, it's an easy fix if you can budget a couple hundred bucks. And it is not impossible that memory constraints are preventing your dependent services from starting as well - or, that a dependent service is starting more slowly than expected because of the memory constraint, which allows a service lower in the tree to effectively 'time out.'
Anyhow, just a few thoughts on it.
Item 1 is a known issue. It's due to a dependency change. It wouldn't surprise me to see that fixed soon (where "soon" is the next rollup or two).
I don't know anything about forefront, but I can tell you right now that I wouldn't install a production Exchange 2007 server with less than 4 GB of RAM and if it's hosting multiple roles, I would look at least at 8 GB. You say "small domain", which is fine, I actually run my home domain on a 2 GB RAM machine – but I've only got 8 mailboxes and I run a/v on my Edge server! I guess what I'm telling you is that 2 GB isn't enough.
Michael B. Smith
I've a small domain with 2 Windows 2003 servers. MS Exchange runs on Server 1 – 64 bit OS. Forefront is enabled to scan incoming e-mail.
I have 2 problems:
1. Many of the exchange server services and the Forefront services won't start automatically and I have to start them manually when I re-boot the server. The symptoms are described very closely in http://support.microsoft.com/kb/951402 but the cause can't be the same as this is a clean installation of Exchange Server 2007 on a 2003 server.
Perhaps the key is that I can't start the FSEIMC service on which other Exchange services depend. However, my exchange e-mail works well internally and externally, in and out, once I have started all the services I can!
2. The memory usage is usually about 4GB (I only have 2GB RAM installed) and a big part of this is due to the 4 instances of FSCRealTimeScanner.exe and the 4 instances of FSCTransportScanner.exe that constantly run – each takes about 140MB.
I rely on consultants to build and configure my servers and the question is do I need to call them in to fix these issues or am I overlooking something more obvious? All help and guidance gratefully received!