Drive paths not stable
I'm having a problem after a tape drive was replaced, our drive paths are now not all being found by Netbackup and the ones it does find are not consistently the same. We have downed everything repeatedly, and rescanned but can only get about half the paths (the number varies). After the tape drive was replaced, Netbackup saw all the paths but marked some as down.
Netbackup is 22.214.171.124 and we have it clustered, with 6 drives and 12 paths to each drive. The drives themselves are in a Quantum Scalar i500 which does seem to be functioning correctly.
Immediately after one drive was replaced all the paths and drives were okay and being used but after a few minutes' drive 1 was shown as down by Netbackup, then came back up, then drive 4 went. Now all the drives are showing as up, but many of the paths are missing.
We think the next step is to reinstall the drivers on each of the boxes to restore the paths, but the concern is that we might then lose all the paths and not be able to complete any duplications to tape, which will mean our disks will run out of space.
Does anyone have any idea what might be causing the instability of the drive paths or how we can fix them?
Background info; while the paths are normally stable we have had to rescan when tape drives are replaced. The current configuration (prior to the drive being replaced) has worked for at least the last 7 months which is as far back as my involvement goes.