I have 4 IBM 3592 E05 drives that I've been using with my commvault system for 3 years now. They're fiber attached to the SAN switched and zoned (in pairs) to my media agents who share them.
Now, I have 2 drives that are acting up on me. One drive says
While accessing a drive the Serial Number obtained  is different from expected Serial Number [0000078F3334].
The F3334 is the actual Ser# on the drive, and 74174 is from another drive I have (which still works).
The way my drives look now is (and this matches their physical layout in the tape library).
Drive 1 - 78F3334 - Unusable due to error I posted above
Drive 2 - 7874513 - Fully Accessible
Drive 3 - 7874173 - Unusable due to error listed as " SCSI-2 Reservation Command to the Drive failed"
Drive 4 - 7874174 - Fully Accessible
I've tried rebooting my media agents. Is this an issue with IBM? Possibly a zoning change on the SAN?