Exchange 2010 Hyper-V Guest Backup (Host Level Snapshot & separate backup of DAG DBs) - Is this OK?

Posted on 2012-08-22
Last Modified: 2013-11-06

I'm really hoping we have some good Hyper-V / Exchange 2010 / Data Protection Manager 2010 experts out there that can assist with this question!

I have the 2 Hyper-V host systems (Win 2008 R2) and each has 2 Exchange 2010 guest VMs (a CAS/HT and a Mailbox).  I have the Mailbox Servers in a Database Availability Group which spans the 2 Hyper-V hosts.  For simplicity, here is breakdown:

 - VM#1 = CASHT1
 - VM#2 = MAILBOX1 (member of DAG)

 - VM#1 = CASHT2
 - VM#2 = MAILBOX2 (member of DAG)

I've installed the DPM agent on both Hyper-V hosts (plus the 2 VMs in each host).  

When I created my first Protection Group, I had it just backup the DAG, selecting all DBs on MAILBOX1 (the active) as full backup and all DBs on MAILBOX2 (the passive) as COPY.  That seems to be working well.

The tricky part is I want to also backup the actual MAILBOX1 and MAILBOX2 VMs, not just the Information Store (mailbox DBs) they have in them.  

QUESTION - Should I backup the MAILBOX1 and MAILBOX2 VMs at the host level or guest level?

I'd like to do it at host level, but:

1.  I am worried that a "snapshot of child partition" backup that will be done at host level may mess up my Exchange DBs and Logs.
2.  I'd like to omit drive D: (DBS) and drive E: (Logs) from the MAILBOX1 and MAILBOX2 backup since I'm already backing them up via the DAG.  The host level backup does not appear to let you omit certain drives.  Otherwise, I'm doubling my backup space usage because I'll be backing up the databases twice (once via host's snapshot of child and once via DAG backup).

Any thoughts?
Question by:dpmoney
    LVL 20

    Expert Comment

    by:Svet Paperov
    Snapshots: you should not use snapshots in production environment, especially on Exchange.

    Backup on the host: if you do host level backup, you cannot truncate the logs files and you cannot restore a single mailbox database.

    Backup on the guest (the mailbox) server: if you have separated the OS and mailbox databases/transaction logs on different volumes you can do two backups: one of the server (system volume and program files) and one for the mailbox databases only with truncating of the log files. The first backup can be used to do server restore in case of server crash while the second one can be used to recover database or even mailbox: example, in case of mailbox database crash, you can restore the last database backup and pay the transaction logs to get all database modifications after the backup. If you had do host level backup only, that "play" wound't be possible.

    Author Comment

    When I mentioned Snapshot, it is a child partition snapshot that is carried out by Microsoft System Center Data Protection Manager 2010 via Volume Shadow Copy, not the Snapshot you are thinking of where all changes from a certain point are tracked and can be rolled back if desired.

    Are you familiar with Data Protection Manager 2010?  This question is very specific to that product and Exchange 2010 Database Availabilty Gropu backups under Hyper-V using DPM 2010.  

    I apprecate the feedback, but your response is not specifically what I'm looking for.  I've attached a graphic to help make it clearer.
    LVL 27

    Assisted Solution

    Hi dpmoney,

    You're in a situation many end up in. Your assessment is spot on i'm afraid.

    To protect the actual,VM and all its settings you need to do the snapshot at host level.
    This works great for the server and its settings, but will not work for database systems like Exchange.

    In general, the most appropriate system to use is the following:

    a) Host level backup of entire VM once a week (as the server doesnt really change much day to day)

    b) Daily backup of the Exchange store, and the logs if possible.

    In the event of a total failure, you restore the VM, then restore the most recent exchange DB.
    If just the DB fails, you can just restore the DB to the working VM.

    Author Comment

    Dear Totallytonto,

    Thanks so much for the feedback.  Glad to see somone familiar with all 3 products also providing their opinion.  I will likely have no choice but to move forward with the dual backpus like you mentioned above.  That way, I'll have a backup of the Exchange VM and also have a backup of the Exchange information store at the app level.  The only part that REALLY bothers me about that is I expect to have a sizable Exchange database (4 of them actually) and this solution will cause me to have duplication in what I'm backing up (the exchange DBs) and storing on DPM 2010.  Basically, the Exchange VMs break down as follows:

    C:   OS

    I would love to do the backup of the Exchange VM as described above, but is there any way to tell DPM 2010 to not capture E: and F: drive?  If not, I guess I'll just have to live with the duplication.  Finally, will the VM level backup do anything to mess up the Exchange DBs or logs in term sof interfering with my appliication level backup.  I assume not, but am just making sure.  Thanks!

    I look forward to your feedback!
    LVL 7

    Accepted Solution

    dpmoney, it is not possible to tell the Hyper-V writer to exclude certain volumes from a VM backup as per
    Now, if the volumes would be pass-thru disks (as per Microsoft Best Practices for Exchange in a VM:, they would be excluded automatically.

    Your question about VM level backup compatibility with application level backup of Exchange is answered in here:
    Both host level and client level will truncate transaction logs, so there would probably be a conflict. The registry key should prevent host level backups from truncating Exchange transaction logs.

    Maybe you should consider doing only host or only client level backups? Why would you need host backups if the Exchange server is only a default server (i.e. from a template) with only Exchange on it.
    If the Exchange server dies, you would deploy a new server from a template and then install Exchange with "RecoverServer" option: the

    Author Closing Comment

    Thanks for initial feedback Totallytonto.  Also, many thanks for denbosse for the detailed data and links!  I'm moving forward with the DAG as is for general high availability, hourly snapshots of Info store in DPM 2010 with nighly full on one MBX server and copy backup on 2nd MBX server.  I've confirmed this approach is clearing the transaction logs.  I expect the mailbox DBs will get large so I don't want to store them twice on DPM server with app level backup and host level backup.  If I get into a total loss situation, I'll rebuild MBX server using the /m:recover option which should be fine.  In terms of the pass-thru disks vs. VHD, I did a lot of reading on this.  The servers are pretty high-end with fast disks in RAID 10 for underlying hardware, plus there are less than 100 users so I think performance will be OK.  Thanks again!

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