PowerProtect DM: DISASTER_RECOVERY Backup Includes All Server Drives Due to VSS Writer Content

During a DISASTER_RECOVERY:\ backup, the size of the backup is huge due to all available drives being included on the backup for no apparent reason.

The DISASTER_RECOVERY:\ asset type relies on Volume Shadow Copy Service (VSS) writer content to determine which drives are critical. When third-party software such as Microsoft Azure Storage Sync Agent is installed, it registers a VSS writer that references all synchronized drives. This causes the DISASTER_RECOVERY:\ backup to include those drives even if they do not otherwise meet the criteria for critical volumes.

During a DISASTER_RECOVERY:\ backup, this asset includes all disk considered as critical on the backup.

For a drive to be considered as critical certain conditions are required:
 

• Any volume that contains files for an installed service. 
• Any parent volume with a mounted critical volume
• All volumes on all dynamic disks critical if at least one of the volumes is critical. A Windows Bare Metal Recovery recovery requires a current backup of all critical volumes.

This specific use case describes a specific scenario where the affected server replicates their local data into the Azure Cloud environment.

In order to replicate local data into Azure cloud, Storage Sync Agent software was installed on the host, which installs Microsoft VSS writer Sync share service, and this writer contains information for all drives which are synchronized with Azure.

Since DISASTER_RECOVERY:\ asset relies on content of VSS writers, all drives are included, even if they do not meet the requisites to be considered as critical drives.

This behavior is by design.

A Request for Enhancement (RFE) PPAS-I-1254 has been raised to add the ability to skip selected VSS writers from the DISASTER_RECOVERY:\ backup scope. This enhancement must be evaluated and approved or rejected by product management. No timeline for the enhancement has been announced.