Re: tape drives

[Steve Scherbinski <sski@xxxxxxxxxxxxxxxx>]

Bruce Smith wrote:
> 
> a backup-software skeptic.
> >
> > The problem with tar and cpio that the better commercial backup software
> > corrects is that the commercial software verifies the tape after writing
> > where tar doesn't.  It doesn't matter how fast your backup/restore is if you
> > don't have a good backup and your data is corrupt.
> 
> I was told once that DDS tapes verify after writing in the hardware.
> 

If you look at the specs most tape drives just do a very simple verify,
though I believe that the DLT drives are different.  I've seen tapes
that were backed up with no errors that you were not able to read
anything off them at all.  Just this last month, a user of mine wanted a
file off a 8mm tar backup tape, and no matter what system we tried it on
we were not able to read it.  If you have a regular backup schedule with
rotating tapes you may be ok, but I would still try to go through and
get at least a table of contents off the tape once in a while.  It all
comes down to what your data is worth and the costs to re-create it. 
Your mileage may vary.

Steve