From: Degerness, Mandell MSER:EX (Mandell.Degerness@gems2.gov.bc.ca)
Date: Mon Jul 08 2002 - 19:09:23 EDT
Thanks to:
Selden E Ball Jr
Dr Thomas Blinn
Steve Herber
Stan Horwitz
Alan Nabeth
for their suggestions. I had already determined that the errors were hard
errors at the O/S level (from dd and uerf). I had also tried reading the
data on 3 different tape drives on two systems (one of which was the
original). What finally worked was reading one of the tapes on a DLT8000
drive attached to a Sun system! Only one of the tapes is readable even
there. (I am creating new archives of the data as I write this :-).
Regards,
Mandell Degerness
-----Original Message-----
From: Degerness, Mandell MSER:EX
[mailto:Mandell.Degerness@gems2.gov.bc.ca]
Sent: Friday, July 05, 2002 4:41 PM
To: Tru64-unix-managers (E-mail)
Subject: Suspicious Bad Tape Blocks
A couple of years ago, I created an archive of some data using Gnu tar.
Being the paranoid type, I actually created two copies (on separate media),
now I can't recover it (the media is Compaq Tape III). The archives were
created slightly differently. One had all files in the directory, the other
had only the SAS data files. The total amount of data backed up was close
to 2 GB. Both archives were verified just after they were created and were
fine as of that time.
On the first tape I get this result (the archive is the 5th file on this
tape):
(eagle|crdormut)root:175 > mt -f /dev/nrmt0h fsf 4
gtar -tvf /dev/nrmt0h
(eagle|crdormut)root:176 > gtar -tvf /dev/nrmt0h
-rw-r----- crdormut/hlth_phr 0 1997-02-14 16:08 agedata.prn
-rw-r----- crdormut/hlth_phr 3737 1997-04-28 11:42 ahdins.prn.Z
-rw-r----- crdormut/hlth_phr 16651 1997-05-11 22:31 all.ssd04.Z
-rw-r----- crdormut/hlth_phr 730 1997-04-25 13:49 ccbdins.prn.Z
-rw-r----- crdormut/hlth_phr 193421087 2000-02-03 16:23 denom.ssd04.gz
gtar: Read error on /dev/nrmt0h: I/O error
gtar: Read error on /dev/nrmt0h: I/O error
gtar: Read error on /dev/nrmt0h: I/O error
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Memory exhausted
(eagle|crdormut)root:177 >
The second tape has the data at the start of the tape (no mt required):
(eagle|crdormut)root:143 > gtar -tvf /dev/nrmt1h
-rw-r----- crdormut/hlth_phr 16651 1997-05-11 22:31 all.ssd04.Z
-rw-r----- crdormut/hlth_phr 193421087 2000-02-03 16:23 denom.ssd04.gz
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Skipping to next file header
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
-rw-r----- crdormut/hlth_phr 16651 1997-05-11 22:31 all.ssd04.Z
-rw-r----- crdormut/hlth_phr 193421087 2000-02-03 16:23 denom.ssd04.gz
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Read error on /dev/nrmt1h: I/O error
gtar: Too many errors, quitting
gtar: Error is not recoverable: exiting now
(eagle|crdormut)root:144 >
What is suspicious (to me) is that the I/O errors occur on the same part of
the file in each case.
I have tried using "dd if=/dev/nrmt0h conv=noerror,sync bs=10k | gtar -tvf
-" as well and dd still reports I/O errors.
Any suggestions?
Regards,
> Mandell Degerness
> Senior Systems Programmer
> Planning and Engineering
> Common IT Services
> Phone: (250) 387-5877 Fax: (250) 387-5231
> email: mailto:Mandell.Degerness@Gems2.gov.bc.ca
>
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