Snapshot for Exchange 2010 Virtual Machine on Esxi 5.0

[Wajeeh]

Dear Experts,

We have exchange 2010 VM running on windows 2008 R2 on Esxi 5.0. I need to do windows updates on this machine. I want advise if it is ok to take snapshot of exchange 2010 machine before performing windows updates and then delete the snapshot once updates are completed successfully, OR it is not good to go for snap shot and revert back in case of problem due to exchange 2010 application behavior I/O.

Please share your views.

Kind Regards,

Wajeeh

[MKguy]

First, let me say that Microsoft does not support snapshots on virtualized Exchange 2010/2013 Servers :

http://technet.microsoft.com/en-us/library/jj126252%28v=exchg.141%29.aspx#BKMK_ExchangeStor

• Virtual disks that use differencing or delta mechanisms (such as Hyper-V's differencing VHDs or snapshots) aren't supported.
• Some hypervisors include features for taking snapshots of virtual machines. Virtual machine snapshots capture the state of a virtual machine while it's running. This feature enables you to take multiple snapshots of a virtual machine and then revert the virtual machine to any of the previous states by applying a snapshot to the virtual machine. However, virtual machine snapshots aren't application aware, and using them can have unintended and unexpected consequences for a server application that maintains state data, such as Exchange. As a result, making virtual machine snapshots of an Exchange guest virtual machine isn't supported.

However, unless you have a very high IO load on the VM, snapshotting should have no negative impact. If you have a DAG cluster, you might see a failover occurring during snapshot creation/deletion.

The real mess can kick in when you actually need to revert to the snapshot: Since it's not application aware, consistency of logs and databases might be affected.

However, you can still take advantage of snapshots for Exchange VMs and consistently restore them if you're ok with a short additional downtime by either:

a) Shutting down the VM temporarily for snapshot creation

b) Temporarily stop all Exchange and transaction based services inside the OS, then take the snapshot and start the services again afterwards

Whether these approaches are actually supported by MS is a different story, but they will at least provide you with a consistent state, which would not be guaranteed if you were snapshotting a live Exchange (or any other transaction-based application) VM during normal operations.

[Wajeeh]

Hello MKguy,

many thanks for detailed response on this case. So in first place MS don't have support for snapshots.

Yes, this could be done turning off VM temporarily for snapshot creation purpose, then power it back on do the updates of windows. But by the way in this case once the updates are successful and we want to delete the snap shot which we took earlier by turning off the VM, for its removal , we again need to turn off the Exchange 2010 VM ?

If we don't take any snap shot for this VM we can also directly proceed for windows updates as we do in case of physical exchange server, right ?

Kind Regards,

[MKguy · Accepted solution]

But by the way in this case once the updates are successful and we want to delete the snap shot which we took earlier by turning off the VM, for its removal , we again need to turn off the Exchange 2010 VM ?

No, you don't have to. Powering off the VM functions as a precaution to make sure you capture a consistent snapshot state of the VM and it's filesystem/databases, in case you have to eventually restore the VM. It's not necessary when removing the snapshot.

Near the end of the snapshot removal operation, the VM will be shortly stun/unstunned to merge the last outstanding blocks into the base disk. This essentially shortly pauses the VM to prevent it from issuing IO and creating more delta data, but this is transparent to the Guest (similar to a vMotion). You may see a ping loss or two, or DAG clusters might initiate a failover because the VM is shortly unreachable, but it should have no impact on or be noticeable by the Guest.

The merge of the snapshot delta back into the base disk can take some time, depending on how large the delta grew in the meantime and how much data continues to change during the removal. The process will place some additional IO load on the storage, so I'd generally recommend doing the delete operation during off-peak hours. Also make sure you have enough free space on the datastore to accommodate the delta file growth.

If we don't take any snap shot for this VM we can also directly proceed for windows updates as we do in case of physical exchange server, right ?

Yes, there is no difference to physical systems in that regard.

[Wajeeh]

Dear Sir,

many thanks for addressing this and providing right guidence.

Kind Regards,

Wajeeh

[AlbertWT]

Hi Guys,

Do you need to turn off / stop all of the Exchange Server services during the Service Pack or applying Windows Update ? [especially for the mailbox server role].

I'm planning to take the VM snapshot during the Windows update and applying the Service Pack, but somehow I wonder if the Exchange Server services needs to run during the process ?

my concerns is that when rolling back the changes, the email for the users which was received during the maintenance window would be rolled back or missing.

[pradeepvenkates]

Hi All,

In of my case, my customer had upgraded the ESXi 5.5 U2 to 5.5 U3a which made the Exchange server services to peg for CPU resources. Snapshot task never failed.

The snapshots on the Microsoft Exchange server is actually not supported.

( KB http://kb.vmware.com/kb/2053985 and

Exchange 2010 -> http://technet.microsoft.com/en-us/library/jj126252.aspx )

Microsoft denied any support on this issue for my customer as this is not supported

We fixed this issue by lowering the hardware version to 8. Lowering the vmware tools to previous version did not work.

Post lowering the hardware version, we never saw any services peg for CPU resources.

[AlbertWT]

pradeepvenkatesh‌ That's very weird but yes, may I know which service is requesting for more CPU ?