On Wed, Mar 12, 2014 at 04:55:30PM +0000, Dave Ewart wrote: > On Wednesday, 12.03.2014 at 12:28 -0400, Jon LaBadie wrote: > > > A guess only. > > > > I note the measured speed has dropped by 45%. Due to what I haven't a > > clue, but maybe some hardware change or cables or ??? > > Hmmm, yeah: I noticed that too, just after I'd posted. It's the same > controller card as always and the same cables, so it's either a driver > issue with the controller (OS has been upgraded once or twice) or a > fault with the controller or damage to the cable, maybe.
All those things, plus, is the controller dedicated to the tape drive? If not, maybe other devices on the same controller are competing for bandwidth. > > > Perhaps your system's ability to feed the drive has dropped below the > > minimum needed to keep the drive streaming. In that case, the drive > > must "shoe-shine" and each restart costs a bit of tape. > > Would this behaviour be noticeable just by looking at the drive in > operation, do you think, seeing some kind of stop and start? Backups > normally run during 'out of hours', but I can run a job while physically > sat in the room with the drive... You could run amtapetype :) If you can hear the drive when it starts and stops (and possibly a different sound when it rewinds) you might be able to hear it regularly changing when it should be constant except when it reaches the end of a track and must reverse to tape the next track. -- Jon H. LaBadie [email protected] 11226 South Shore Rd. (703) 787-0688 (H) Reston, VA 20190 (609) 477-8330 (C)
