Exchange 2007 to Virtualize or Not

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Mar 15, 2002
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We will be deploying Exchange 2007 very soon and I'm wanting to use ESXi for this. We are already running our web servers on two Dell 1950 III running ESXi with great success so far. I've really been impressed.

Currently we have just under 70 mailboxes and that won't be growing anytime soon in the least. I also have a box spec'd out already that would do the job, a Dell 2950 III. The question is whether or not it is safe, viable, recommended to virtualize Exchange. I was kind of hoping to hear some first hand experiences with virtualized Exchange deployments in a production setting.

Any advice or comments are appreciated.
 
We have the majority of our Exchange 2007 servers virtualized. We have 2 CAS servers, 2 Edgeservers, and 2 Hub servers in ESX with no issues. Our mailbox store is not in vmware because it already utilizes the hardware fully (dual quad core with 32GB ram). I would recommend calculating out your disk access usage as it is the mostly likely thing to cause slow down. I suspect with that few of users though, it will handle it without issue.
 
VMware ran some tests that showed a concluded that a single proc vm could host thousands of mailboxes... take those numbers with a grain of salt, however.

Exchange 2007 is more memory dependent than disk I/O, unlike previously. There are many enterprises running virtualized Exchange 2007 infrastructures. Safe, viable and reccomended, I say yes.
 
Because of the way that ESX handles the IO requests to CPU, RAM, Disk, and NICs, it is very efficient at scheduling those resources. VMWare recommends always testing a new VM (or P2V migrated server) with a single vCPU. It will almost always outperform 2x vCPUs, or 4x vCPUs.
 
If you are spec'ing out a server for exchange... why the heck would you want to virtualize it ?
 
because he could run a lot more than just an exchange box, with that kind of hardware, if he ran ESX
 
because he could run a lot more than just an exchange box, with that kind of hardware, if he ran ESX

Exactly. Exchange is just one piece of the puzzle for this new box. I spec'd the box out to make sure it would run Exchange in a VM if I did go that route. I will run approx four to five more vms on this new Dell 2950 III along side the Exchange VM.
 
If you have SAN storage - use an RDM. Exchange much prefers direct disk access for its databases :)
 
If you have SAN storage - use an RDM. Exchange much prefers direct disk access for its databases :)

VMFS is nearly as fast as RDM. Use RDM maybe for logs only, but RDM ties your VM to your SAN. Isn't one of the points of virtualization to de-couple the OS from hardware?

VMware's best practices are also to use RDM only if you need to cluster or utilize SAN-specific capabilities.

Lastly, Exchange 2007 trades memory over disk I/O, unlike 2003. You can further reduce I/O by enabling cached exchange mode in Outlook. I've read that I/O has been reduced by as much as 70% going to Exchange 2007 vs 2003.
 
VMFS is nearly as fast as RDM. Use RDM maybe for logs only, but RDM ties your VM to your SAN. Isn't one of the points of virtualization to de-couple the OS from hardware?

VMware's best practices are also to use RDM only if you need to cluster or utilize SAN-specific capabilities.

Lastly, Exchange 2007 trades memory over disk I/O, unlike 2003. You can further reduce I/O by enabling cached exchange mode in Outlook. I've read that I/O has been reduced by as much as 70% going to Exchange 2007 vs 2003.

Exchange has some significant performance increases on RDM vs VMFS volumes, especially given the high IO load - it will often crowd other vms off of the same volume with contention for the lun.

AFAIK, the recommendation is still to do an RDM for exchange 07 - it definitely was for 03.

Lun copys to move the vm from the san to another are not hard - an RDM will travel just as well as a vmdk if you have a decent san admin :)
 
Exchange has some significant performance increases on RDM vs VMFS volumes, especially given the high IO load - it will often crowd other vms off of the same volume with contention for the lun.

AFAIK, the recommendation is still to do an RDM for exchange 07 - it definitely was for 03.

Lun copys to move the vm from the san to another are not hard - an RDM will travel just as well as a vmdk if you have a decent san admin :)

Normally you wouldn't dedicate a mailbox store onto a LUN with other VM's. Contention is a given, which is why you dedicate a VMFS lun to 2k7.

I would like to see the RDM reccomendation for 2k7 because AFAIK, VMFS is the way to go for all the reasons why you go virtual in the first place. I have a feeling RDM will be deprecated in the future as VMware starts to unify different vendors more. For 2003, yes you should probably use RDM. 2003 is not as optimized as 2007. Then again, probably not many people virtualized 2003 to begin with for those reasons.

If you're overly concerned about RDM performance over VMFS, you probably shouldn't virtualize in the first place.
 
Normally you wouldn't dedicate a mailbox store onto a LUN with other VM's. Contention is a given, which is why you dedicate a VMFS lun to 2k7.

I would like to see the RDM reccomendation for 2k7 because AFAIK, VMFS is the way to go for all the reasons why you go virtual in the first place. I have a feeling RDM will be deprecated in the future as VMware starts to unify different vendors more. For 2003, yes you should probably use RDM. 2003 is not as optimized as 2007. Then again, probably not many people virtualized 2003 to begin with for those reasons.

If you're overly concerned about RDM performance over VMFS, you probably shouldn't virtualize in the first place.

Actually, RDM will only become more important as we gain the ability to give more direct access to hardware to VMs - look at NPIV, for instance, which will eventually give vms direct access to san luns outside the ESX box.

RDMs give you performance while still maintaining the ability to vmotion, migrate, HA, etc. There are lots of reasons to virtualize a machine that needs lots of direct access. Hardware maint, etc is all eased via virtualization.

MANY MANY MANY customers used 2k3 and exchange on ESX. Many. It's extremely common, actually, and performance is better with the RDM. Not many are doing 07 yet since its' still new, and most want to run it on win2k8, where support has been "questionable" for some time.
 
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