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:
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.