Exchange VM for 75 users?
Posted on 2011-05-04
I'm researching a 75 user Exchange 2010 SP1 build. This will be virtualized, as our VMware servers are currently averaging about a 8% load. I'm trying to use the Exchange 2010 Mailbox Server Role Requirements Calculator, but it seems my requirements are so meager that most of the results are left blank even after I fill in as much data as I can. So, I turn to you!
I've not used Exchange since 2003 - at that time, with the same 75 users, virtualizing was no problem at all. The VM ran at about 5% utilization with only 2GB RAM and 1 vCPU. I see that 2010 has added a number of new roles, all of which can run on the same VM, but how much extra overhead does that imply?
Our users will not be sending many images or large attachments, but we have 1 9GB mailbox, 1 5GB mailbox, and the rest are mostly 500MB mailboxes. The vSphere host is 8 core 2.6 55xx series, with 16x2.5" 15K SAS in a RAID 10. It has 10 VMs currently, but I could migrate 4-5 of those to a different host if necessary.
A few specific question that I have:
Should I break up the roles and separate them on to our 2 hosts (we only have 2, equal in hardware)?
Is there any point to creating multiple VMDKs since they all reside on the same physical LUN? I've read that you can run the risk of filling partitions with logs and IS, which would crash the box entirely, and that's the main reason to do so.
The calculator recommends 8GB RAM and 2 databases but only 1 CPU? could that be accurate for such a small user base?
We will be doing weekday full backups with BackupExec which should commit/flush logs.