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g_pozdnyakov's avatar
g_pozdnyakov
Level 2
10 years ago

VMWare VM backup destroys shadow copy of a file backup job

Hello, everyone.

Recently we ran into an issue with overlapping backups. We have defined some backup jobs and one of them is taking a long time to be finished because of a huge amount of data. This job is a file backup job running for 4 days in the end of the week. It includes all the data from RDM disk mapped to a file server VM. This RDM disk is configured to be persistent independent disk. BE 2014 RAWS is installed on this server.

Another job is configured to run VMWare VMs backup in the end of the week. This job includes a bunch of VMs including the file server VM. RDM disk is excluded from the backup. The only disk included into it is a system disk of the file server VM.

All the servers are running Windows Server 2012 R2 Standard.

So, consider the following scenario:

1)  We start a file backup job manually. After that we check the results of vssadmin list shadowstorage and vssadmin list shadows commands on the server which is the only server included into the file backup job. You can see the results on the following screenshot:

vssadmin_01.png

2) Next we start a VMWare VMs backup job.

3) Both of this backups are running simultaneously until the second one reaches the file server. To backup this VM this job requests to create a snapshot of VM and we can see this in a vSphere Client.

4) After that we can see that there is no shadow storage on this server and no shadows created previously on the first step by the file backup job.

vssadmin02.png

5) After that in few seconds the first backup job stops with an error telling that some files are not accessible.

I had a conversation with a support engineer last week  and got the information that this two backups should work together with no errors. Maybe there is any misconfiguration or something else. Please, let me know if you ran into the same issue and if you have a solution or any idea about this situation.

 

Backing Up
Backup and Recovery
Backup Exec
Virtualization

4 Replies

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  • VJware's avatar
    VJware
    Level 6
    10 years ago

    This job includes a bunch of VMs including the file server VM. RDM disk is excluded from the backup. The only disk included into it is a system disk of the file server VM.

    How exactly did you specify the exclusion of a disk from a VM ? (afaik, this isn't supported, its either the complete VM or none exclusion)

     

  • g_pozdnyakov's avatar
    g_pozdnyakov
    Level 2
    10 years ago

    How exactly did you specify the exclusion of a disk from a VM?

    This disk was excluded using Include/Exclude rules. I've seen some articles and discussions about exclusion rules too, but we use them into another environment with no problems. All the excluded VMDK files were never backed up.

    To verify this I've created a test backup of our SQL server with an additional VMDK which is excluded from the backup. You can see the selection list on the following screenshot:

    selectionlist1.png

    On the next screenshot you can see the "Selection details" tab of this selection list:

    selectionlist2.png

    And here are the results of Full and Incremental backups of this VM:

    Full-backup-res.png

    Incr-backup-res.png

    As you can see, only one VM disk was backed up with no errors during Full and Incremental backups. Actually, this is not an RDM disk but this test confirms that we can use exclusions for VMDK files during VM backup.

    Anyway, I don't think that any exclusion is a real reason of shadow copy failure. It seems like this error appears while vCenter processes a snapshot of VM while there is another VSS shadow copy for a volume in a VM. I'm really wondering why do we loose shadow storage configuration and a shadow copy of the volume while Microsoft VSS supports up to 64 shadow copies of the volume.

  • VJware's avatar
    VJware
    Level 6
    10 years ago

    The idea is we do not support exclusions of such a type and hence, such a situation shouldn't exist in the first place. Snapshots should not be used in conjunction with VMs containing RDM disks and i believe if debugging is enabled, it will show the limitation.

    Here is a KB stating the non-supportability -

    http://www.symantec.com/business/support/index?page=content&id=TECH189056

    http://www.symantec.com/business/support/index?page=content&id=TECH124365

  • g_pozdnyakov's avatar
    g_pozdnyakov
    Level 2
    10 years ago

    This articles are related to BE 2010 and BE 2012. I forgot to mention that we use BE 2014 SP1.

    Even if this articles are related to BE 2014 too, then how could I be able to perform backups with exclusion successfuly?

    Snapshots should not be used in conjunction with VMs containing RDM disks

    Are you talking about AVVI only? Why does a vCenter snapshot processing destroys VSS shadow copies inside the machine? I'm going to check this on another machine to verify if this issue exists when I create a shadow copy manually and then create a VMWare snapshot.