I've receintly upgraded from the 20/40 to the 40/80. backward read compatability is fine, however, you can NOT relabel the 80 gig tapes that were previously labeled in 40 gig mode. The tapes need to be bulk erased 1st. I tried bulk erasing with the most powerful magnetic field we had in the media dept. to no avail. Amanda still read the labels. fyi David Wolfskill wrote: > >From: Alexandre Oliva <[EMAIL PROTECTED]> > >Date: 18 Nov 2000 05:51:47 -0200 > > >(i) in case the DLT4000 robot fails, the DLT7000 tape drive will be > >able to read backups done with it, and > > >(ii) after the DLT4000 robot is fixed, it will be able to read tapes > >written by the DLT7000 drive. > > The autoloader with which I started using amanda was a 7-slot ADIC > device with a DLT 4000 drive (August, 1998). > > I had told my manager that sometime around spring of this year, we > should plan on going to a DLT 8000 drive. We did this (though it took > longer than expected); it arrived in mid-October, just before I went on > a 2-week vacation (for the first time in years). > > Since we have a dedicated amanda server, it isn't being used when the > backups aren't running (and I'm not tweaking it); I was able to swap the > devices and do some preliminary testing. Basically, the drive worked > just fine without making any changes to the amanda configuration -- > though we weren't making optimal use of its capabilities. > > Given that I was going to be out of the office for a while, I chose to > leave well enough alone until my return. > > After I got back, I found that amanda had run trouble-free; given that, > I started making changes to take advantage of the DLT 8000 -- briefly, > it holds twice as much (40 GB vs. 20 GB native) and writes as much as > four times (6 MB/s vs. 1.5 MB/s) the DLT 4000 drive. (Tape writing > speed is nowhere near the bottleneck now.) > > >From this, we may observe that the DLT 8000 drive had no trouble reading > the tapes that had been written with the DLT 4000 drive -- I did not > need to re-label the tapes (via amlabel), for example. And I believe I > did a restore or two, using the DLT 8000 drive, from backups that had > been written with the DLT 4000 drive. > > Although I have not tested it, I would not expect that the DLT 4000 > could read tapes written by the DLT 8000, though -- unless there's some > way to force the DLT 8000 to *write* in DLT 4000 mode, which I doubt. > > I would expect similar considerations to apply to a DLT 7000. > > Cheers, > david > -- > David Wolfskill [EMAIL PROTECTED] UNIX System Administrator > Desk: 650/577-7158 TIE: 8/499-7158 Cell: 650/759-0823
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