Restore to 9.2 client from a Data copy saveset fails with 'Failed to get index" (4041360)

A NVBU 9.2 client is successfully backed up by a NVBU 11 server.

The backup is also successfully data copied to tape and the original phase 1 expired.

Any attempt to restore the 9.2 data copy saveset back to the client fails with:

"Failed to get index".

Trace from the server and client show that the index in successfully copied from the NVDB to the client's netvault/tmp, but the File System plugin on the client fails to read the index version 4:

Backup Indexes under NVBU 9.2 are of type Version 3 while NV10 and 11 produce backup indexes of type Version 4.

Restoring backups taken from 9.2 clients is possible and fully supported from a NVBU 11 server, this is because during backup it is the client that creates the backup index in version 3 then sends it to the NVDB and media to store.

During restore this same version 3 index is sent back to the client and the client can read the version 3 index successfully.

Now during Data Copy jobs, by default, it is the server that runs the job and will create a new version 4 index for this backup.

During restore, if the original phase 1 is no longer available, the version 4 data copy index is sent back to the client but the File System plugin on this 9.2 client won't be able to read this version 4 index and will fail with the above errors.

To allow for the restore to complete consider these options:

- If the phase 1 backup is still available, restore from it, which should work.

- If the original phase 1 backup has expired but still on media, scan it to retrieve it and perform the restore from this saveset.

- If the phase 1 cannot be retrieved, you will have to upgrade the client to NV10 or 11 so the upgraded File System plugin can successfully read and process the new version 4 backup index, and initiate the restore.