Microsoft Virtualization Discussions

SMHV, SM for SQL and Pass-through disks how to backup?



We use SMHV for our backup solution for all our VM's and it works great!

Now we want to virtualize our SQL server. We created a VM and a couple off pass-through disks.

SMHV can't backup the machine because he has no access to the (luns) pass-through disks and the backup is Failed for all the VM's.

Ok, we installed Snapmanger for SQL and we make a backup and a mirror of the machine database. There is my point, no backup of the VM.

We want to separate the databases from CSV because we need seperate spindels for the databases and the VM's.

I did not try to make 5 new CSV volumes and put them in the cluster. Each new volume will have only one vhd file.

Those vhd files pointing to the SQL server and they are backuped with SMHV. But then I can not use SM for SQL because snapdrive (in the VM) does not see the luns?

So how can we make a good solution?




Re: SMHV, SM for SQL and Pass-through disks how to backup?


Hi Perry,

Even if a VM has one or more pass through disks attached to it, SMHV should be able to take backup of the VM successfully. The VM backup will not contain the data on pass through disks, but the backup itself should succeed and all the VHDs associated to the VM will be there in the backup.

A possible reason for failure of VM backup with pass through disks could be that the following hotfix is not installed:

Can you please check if this hotfix is installed on the Hyper-V parent?

If not, please install the hotfix on Hyper-V parent host and then update the integration services in each VM.



Re: SMHV, SM for SQL and Pass-through disks how to backup?


Hi Anagha,

Thanks for your quick response!

The hotfix was already installed but there is nothing about pass-through disks.

I hope you have right that it is possible!

The error from microsoft eventlog is:

One or more physical disks are attached to virtual machine 'mySQLServer'. Back up programs that use the Hyper-V VSS writer cannot back up volumes that are attached to virtual machines as physical disks. To avoid potential data loss, use another method to back up the data on the physical disks. If you restore the data on this virtual machine, make sure to check the data of the physical disk for integrity. (Virtual machine ID 12345).
The error from SMHV is:
[8-10-2010 12:01:56, (5)] Initializing VSS for backup
[8-10-2010 12:01:56, (5)] Collecting VSS writer information
[8-10-2010 12:02:03, (5)] Adding components for backup
[8-10-2010 12:02:03, (5)] Creating snapshot set
[8-10-2010 12:06:43, (5)] Saving VSS writer metadata
[8-10-2010 12:06:43, (5)] Generating backup information
[8-10-2010 12:06:43, (5)] Sending backup complete notification to VSS writers
[8-10-2010 12:06:47, (5)] Saving VSS backup metadata
[8-10-2010 12:06:47, (5)] Writer Microsoft Hyper-V VSS Writer involved in backup or restore operation reported partial failure. Writer returned failure code 0x80042336. Writer state is 5.
Application specific error information:
Application error code: 0x1
Application error message: -
Failed component information:
Failed component: \12345
    Writer error code: 0x800423f3
    Application error code: 0x80004005
    Application error message: Failed to create the backup of virtual machine 'mySQLServer'. (Virtual machine ID 12345)
Perry van Erning

Re: SMHV, SM for SQL and Pass-through disks how to backup?

Once the hot fix is installed on the Hyper-V parent also remember to update the integration services in the VM 
using following menu item
Action -> "Insert Integration Services Setup Disk".
[This will install the newer bits for the Integration packs inside the VM as a part of the Hotfix]

Retry the backup after the integration service is updated for the VM.


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