Backups are failing with messages such as:
An unknown error occurred on device "HP1"
Hardware error on HP1
All the diagnostics run on the drive pass successfully.
If the server is a HP server, check if HP Insight Management is installed and running.
Turn off the HP Insight Foundation Agents & HP Insight Storage Agents and try running the jobs that were failing.
There may be a compatibility issue between Backup Exec, HP Insight Foundation Agents & HP Insight Storage Agents and the LSI Storport driver
Below are 2 links to Symantec documents regarding the problem.