Hi ...

I'm A DBA, the Microsoft provide support for Shared VHDX in 2012. As you know we can run Windows Failover cluster on shared VHDX. Some backup software is taking backup of these VMs under some limitation like cannot use snapshots.

One of these limitation is using VAEEM. they backup VMs in crash-consistent state which mean simply an image can be compared to the state of a VM that has been manually reset. Unlike offline backup,  I don't know  if this is O.k with Microsoft SQL server backup

Hi Sir,

You cannot do host-level backups of the guest cluster. 

You have to install backup agents in the guest cluster nodes and back them up as backing up physical machines.

As it was discussed in the following thread

"Install the DPM Agent an all nodes of the Cluster, after that, create a Protectiongroup, you should see your Cluster as a Ressource"

https://social.technet.microsoft.com/Forums/en-US/b3a20299-2bfe-4b8f-ba7f-20a742caa84f/backup-guest-cluster-with-shared-vhdxs?forum=dpmhypervbackup

Hope it is hlepful to you .

Best Regards,

Elton Ji