Advanced disk pool down

markplayford 

Please forgive me, but I'm battling to piece everything together. 

Here you received 'server name not found' error: 
./nbdevquery -listconfig -storage_server lsabackup01 -stype advanceddisk
DSM was unable to find the following storage server: lsabackup01
failed to get storage server configuration information, server name not found in the NetBackup configuration

Maybe because you used short name instead of FQDN ?  Does the command work when you use FQDN? 

Your last post shows : 
Configured Disk Volume \\qnap\Veritas_Backups is not found on storage server

You say ' .... it's only the unc share of the volume that has changed.'   
Is \\qnap\Veritas_Backups  the updated path? 
Is this the same path that you manually use on the storage server (lsabackup01) to access the path? 

Lastly - NBU logon services - 
Please try this: 
Change these 2 services to Windows user with write access to the storage (you may try your own user name as a test, since you know that is working):
NetBackup Client Service
NetBackup Remote Manager and Monitor Service
(Reference: https://www.veritas.com/support/en_US/doc/62428570-127355758-0/v41399748-127355758   )

Restart these 2 services.

Let us know if there is any progress.