Windows Server 2008 Backup to NAS - strange behaviour RRS feed

  • General discussion

  • Hello,
    I've scripted wbadmin to go to a NAS (I've tried both Windows and Linux based devices) and have noticed this strange behaviour:

    1. No backup history is kept - only the last version, unlike when backing up to USB HDD
    2. The first backup is obviously a full backup so it takes a long time
    3. The second, third, forth, fifth and sixth backups are very fast (a few minutes) so they must be incremental
    4. The seventh backup is slow, so it must be a full
    5. Every 7th backup thereafter is slow, with every other backup being very fast

    So NAS behaves differently compared to USB HDD backups:

    1. No backup history
    2. Every 7th backup is a full; the rest are incremental

    Can you please comment on this? Why is there no backup history, even though it is possible with USB HDD?

    The reason I'm doing this is that in a virtualised environment, the guest doesn't have USB access, so we cannot backup to anywhere apart from NAS. What other solutions are available?


    Wednesday, February 4, 2009 1:18 AM

All replies

  • Unfortunately, "Windows Server Backup" provides very limited options when going virtual.
    WSB will only do MANAGED backups to:
    Local hard drives
    iSCSI drives
    USB or FireWire drives

    An UNMANAGED backup (a single-point backup with no history) can be done to network shares, mapped drives, eSATA drives, etc.

    Since a NAS isn't a "local" drive, you lose it as an option, even when backing up from the parent partition.

    Once you get into Hyper-V, you lose more options. Pass-through drives from the parent OS will work, but if you disconnect them from the parent, your child OS won't like it at all. USB, as you noted, won't work without extra hardware or software.

    I've been trying to find a way to back up directly to USB or eSATA removable drives and am not having much luck. The only "for-sure" ways appear to be:
    1) Use software or hardware that injects USB into Hyper-V children
    2) Set up an iSCSI target (which is probably best done on a separate computer since the "free" iSCSI targets don't play well inside Hyper-V
    3) Do a two-stage backup :
    Stage 1 - back up to a local hard drive
    Stage 2 - copy the backup to a network-shared drive (NAS)

    If other folks have better ways, I'd love to hear about them.

    Myron Johnson
    RTA Information Technology
    Tempe, AZ
    Wednesday, February 4, 2009 3:03 AM
  • Hi Myron,

    Thanks for your reply.

    I agree that there are limited options from Hyper-V.

    I have done hundreds of hours of testing on Windows Server Backup, and I must mention a few things because people need to know these limitations - it's too late to find out when you need to restore.

    1. You cannot copy the backup to a different location and do a restore on the copy. This is because WSB seems to look for a specific drive - ie. \\volume\{guid} and that's in the catalog file of the backup. I tried altering it with a hex editor to see if I could force it, but it wouldn't work.

    2. The limitation of only having one backup is only for NAS, rdx and REV drives. eSata and local drives for example can have multiple versions of backups on the one disk.

    3. The only way that I've found of backing up from within a Guest OS is to backup to NAS - but with the weird effects that I noted in my first post in this thread.

    4. I am currently testing backing up from the host. I have a machine with 6 guests, and am backing it up twice a day to eSata. I'm going to see how much performance degradation (on the guests) there is running a backup from the guest.

    5. There is a piece of software that I have heard about that makes a USB port on a remote machine visible from within a guest, but it's not going to be able to do that when you need to do a bare metal restore, so it's not a solution.

    I will post back my findings on the Hyper-V testing when I have completed them.

    Friday, February 6, 2009 6:16 AM
  • Hi Somaking,

    Sorry if I wasn't much help. Thanks for the information you passed on. I'm always looking for new hints on how WSB works. I've read all the whitepapers and TechNet notes, and I'm still not able to get a solid handle on it.

    The frustrations of working with the limitations of with Windows Server Backup are driving me crazy. Especially with Hyper-V. I can't tell my clients that they can save $2000 on a second server, but will have to buy a $5000 backup solution. It's frustrating because I could do reliable backups/restores with Server 2003, and I could take them offsite. I can't figure out a way to do this with Server 2008/Hyper-V. Especially with SBS 2008 or Exchange Server 2007 as a child OS. Arrrghhh.

    Looking in this Forum at the problems and questions and answers about Server 2008 backups makes it apparent that there are some significant issues and that not many people have an in-depth experience with backups/restores with Windows Server Backup. That's always the case with a new product.

    I take backups and RESTORES very seriously. I refuse to implement technology that I can't properly back up and carry the backups offsite. It appears that Server 2008 R2 and the associated Hyper-V are going to help with this problem by allowing pass-through disks to be removeable. I haven't run R2 yet, but it's next on my list.

    Myron Johnson
    RTA Information Technology
    Tempe, aZ

    Saturday, February 7, 2009 4:36 AM
  • Still waiting for a reply from Microsoft on this.....
    Friday, February 13, 2009 1:24 AM
  • sorry for the inconvenience caused. let me try to answer and take further questions here.

    1. wsb creates a folder structure under the backup location under 'windowsimagedirectory'. to copy a backup, the whole dreictory structure need to be copied. for recovery - it need to be restore to the root of the volume say x: and that can be specified in wbadmin.exe start recovery command using -backuptarget switch. when using UI - another server flow can be used in recovery wizard to select backup location.

    we can discuss this in a separate forum thread if there are follow up questions on how to copy a wsb backup.

    2.  limitation of having only one backup is with network location. this is because wsb uses shadow copies to maintain multiple versions of backup. shadow copies are available on disks only.

    3.  backup can not be scheduled to disk using UI. but it can be scheduled to a volume using wbadmin.exe start backup command and using task scheduler. i have posted earlier on this forum about this. if a host volume can be imported into guest - backup can be done to the volume using these steps.
    again hyperv backup - we can take up on a separate thread if there are further queries on this.

    regarding every 7 th backup is slow - this is because every 7th backup is full

    ------- this information is provided as-is without any warranties, implicit or explicit.
    Friday, February 13, 2009 7:50 PM