gtar failing, please help!

David Bear David.Bear at
Wed Feb 2 17:23:30 PST 2005

On Wed, Feb 02, 2005 at 02:29:26PM -0500, Kevin A. Pieckiel wrote:
> On Wed, Feb 02, 2005 at 02:03:45PM -0500, Kevin A. Pieckiel wrote:
> > I have some backup scripts that manipulate a tape library and tape
> > drive to perform my nightly backups.  Ever since the switch from
> > gtar to bsdtar in the base system, gtar fails to write any data
> > to my tape and usually puts my SCSI bus in an unusable state.  I
> > must then issue a camcontrol reset command to free up the tape
> > drive for use.
> Just for grins, I tried playing with dump.  Dump fails as well:
> # dump -0 -a -b 64 -C 32 -f /dev/nsa0 -n -u -L /    

since you are using a tape, have you checked with 
dmesg (for kernel message about the tape)
mt errstat (cryptic output, but maybe someone here could help)

or rather try

dd if=/dev/zero of=/dev/nsa0 bs=512 count=10000

then play with different bs and count number. This will show you what
your tape block size is -- and if your tape has some kind of crc
error at a block, will also stop consistently at the same location.

for me, my experience down scsi tape units and freebsd has been a road
into the black abyss. I've finally got the tape dumps to work -- but
it took many hours of trial and error. 

btw, I wonder how many tape unit users get burned by the fact that
they don't test their tapes -- and when they need the tape find that
it was bad..

>   DUMP: Date of this level 0 dump: Wed Feb  2 14:27:05 2005
>   DUMP: Date of last level 0 dump: the epoch
>   DUMP: Dumping snapshot of /dev/amrd0s1a (/) to /dev/nsa0
>   DUMP: mapping (Pass I) [regular files]
>   DUMP: Cache 32 MB, blocksize = 65536
>   DUMP: mapping (Pass II) [directories]
>   DUMP: estimated 176863 tape blocks.
>   DUMP: dumping (Pass III) [directories]
>   DUMP: write error 64 blocks into volume 1
> Broadcast Message from kpieckiel at             
>         (/dev/ttyp0) at 14:27 EST...                                           
> Message from the dump program to all operators                              
> DUMP: NEEDS ATTENTION: write error 64 blocks into volume 1                     
> DUMP WRITE ERROR!                                                              
>   DUMP: Do you want to restart?: ("yes" or "no")
> I just don't know what to do.  I'm half tempted to use Windows for
> the fileserver at this point.  I *need* working backups!
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David Bear
phone: 	480-965-8257
fax: 	480-965-9189
College of Public Programs/ASU
Wilson Hall 232
Tempe, AZ 85287-0803
 "Beware the IP portfolio, everyone will be suspect of trespassing"

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