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I am thinking of installing MS Exhange server in windows server 2008 running as a VM inside VMWare Esxi. I am not sure about the performance and reliability. Can anyone provide his experiences in this issue? Thanks

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up vote 9 down vote accepted

This is Microsoft's official position on the subject:; it's related to Exchange 2007, but no more recent article is available; howewer, I don't think much more has changed with Exchange 2010.

Long story short: it will run and it's supported, but you have to plan things well in order to get good performance out of it.

Reliability is as good as the underlying physical host(s); VMware ESX/ESXi are very stable and mature virtualization solutions, so you shouldn't have to worry about your host(s) or VMs behaving erratically and/or crashing.

About performance... it strongly depends on your workload. But if you follow the guidelines for Exchange 2010 capacity planning and add some more CPU/RAM to compensate for virtualization overhead (which is, anyway, quite small), your system should run as well as a physical one.

The single most critical point is, of course, storage. With ESX/ESXi you can use SAN storage just like you would use it with a physical host, and in this case the performance penalty is negligible; but if you're instead running VMs from the host's local storage, then you'll have to take extra care in planning your disk/RAID configuration. Rule of thumb: try not to put too many VMs on the same disk/array, and absolutely don't put two or more IO-intensive VMs (such as Exchange mailbox servers and/or SQL Servers) on the same one.

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Consider RAM vs. Disk I/O.

Exchange 2007 and 2010 with their 64-bit architecture have traded more RAM use for substantially lowered use of the disk. Exchange 2010 can easily support hundreds if not thousands of users with acceptable performance on a single SATA drive. This is assuming you have 16GB+ of RAM available. This was not possible in Exchange 2003 without a substantial RAID setup or many luns on a SAN.

Also consider using the 2010 DAG feature for maintaining availability using multiple VMWare hosts spread out at different points in the network.

Both VMWare ESXi and Exchange 2010 are available for trial periods. I suggest setting up an NFS store using Linux or Even Windows Server and use that to host you Exchange VM. Then use the loadgen tool from Microsoft to see what kind of performance you can get.

The future is Virtualization and, right now, you can't get much better than VMWare. Lab everything up and you'll be good to go.

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We're doing exactly this. We have an Exchange 2007 environment supporting around 4400 users inside an ESX3.5 based cluster. We have four mailbox servers, two Hub/CA servers, and two, edge servers, all of which are in VM. The VM is backed by an EVA6100 storage array. During regular production hours our IOps are very well within the capabilities of the array, and it is only during the Online Defrag process that we seem to push storage to its limit (about 8K IOps). This is solveable by staggering when we do the defrags over when we're not doing backups.

It has been very reliable for us.

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Wow... I have an almost identical setup as sysadmin1138...

Exchange 2007

  • 4 mailbox servers
  • 2 CAS
  • 2 Hub servers

This has been happily running a fourteen node ESXi 4.1 cluster, backed by a Hitachi USP-V / AMS2300. We had been running on an EVA 5000 and 4400, but for some reason the 5000 is just too dang old to be compatible with ESXi 4.1. You'll see LUNs disappearing for no good reason. But that is a story for another day.

We have been very happy with our Exchange VMs, and have had no issues at all.

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