From: senseman@ricky.brainlab.utsa.edu (David M. Senseman)
Newsgroups: comp.sys.sgi
Subject: Problem with Tape Backup -- blocksize mismatch
Date: 26 Jul 92 12:32:33 GMT
Organization: University of Texas at San Antonio

Here's what I get from an Indigo XS-24 running 4.0.5 with List_tape:
/////////////////////////////////////////////////////////////////////////////
ricky 259# mt rewind
ricky 260# mt status
        Controller: SCSI
        Device: ARCHIVE: Python 25601-XXX2.63
        Status: 0x20262
        Drive type: DAT
        Media : READY, writable, at BOT
ricky 261# List_tape

Tape listing started.  Please wait...

Tape Header
===========
bru: warning - missing archive header block; starting at volume 1
bru: c => continue  q => quit  r => reload  s => fork shell  [default: q] >> c

Files
=====
bru: warning - missing archive header block; starting at volume 1
bru: c => continue  q => quit  r => reload  s => fork shell  [default: q] >> c
bru: warning - file synchronization error; attempting recovery ...
s_read req=18432 read =-1
-rwxr-xr--   1 root     sys        33597 Jul 20 12:00 /usr2/src/stud/stud_main.c
bru: warning - file synchronization error; attempting recovery ...
s_read req=10240 read=-1
-rwxr-xr--   1 root     sys         2136 Jul 20 12:00 /usr2/src/stud/butt.h
-rwxr-xr--   1 root     sys         5061 Jul 20 12:00 /usr2/src/stud/button.c
-rwxr-xr--   1 root     sys        24213 Jul 20 12:00 /usr2/src/stud/dir_main.c
bru: warning - file synchronization error; attempting recovery ...
-rwxrwxr-x   1 root     sys        23542 Jul 20 12:00 /usr2/src/stud/datafile.ps
-rwxr-xr--   1 root     sys         5257 Jul 20 12:00 /usr2/src/stud/dcv.c
-rw-r--r--   1 root     sys        50160 Jul 21 12:01 /usr2/src/stud/printinfo.o .......
////////////////////////////////////////////////////////////////////////////////
The script doing the backup is:

#! /bin/sh
/bin/mt -t /dev/mt/tps0d3nrv rewind
/bin/mt -t /dev/mt/tps0d3nrv status
if [ $? -eq 0 ]
then
        echo "Backup /usr2 date:" > /tmp/brulog
        date >> /tmp/brulog
        bru -cBvZT -f /dev/mt/tps0d3nrv /usr2 >> /tmp/brulog
        mt -t /dev/mt/tps0d3 rewind
        bru -i -f /dev/mt/tps0d3nrv > /tmp/bru_errors
        mt -t /dev/mt/tps0d3nrv rewind
else
        elm senseman -s "Backup Errors -- /usr2 backup " < /error_notice.
fi

//////////////////////////////////////////////////////////////////////////////

Here's the top part of the "/tmp/brulog" :

ricky 265# more brulog
Backup /usr2 date:
Sun Jul 26 03:30:06 CDT 1992
c ( 0%)   2k of   4k [1] / <--------------------------------+
c ( 0%)   2k of   6k [1] /usr2                              |
c ( 0%)   2k of   8k [1] /usr2/lost+found                   |
c ( 0%)   2k of  10k [1] /usr2/src                      Files Lost!
c ( 0%)   2k of  12k [1] /usr2/src/stud                     |
c (30%)   4k of  16k [1] /usr2/src/stud/Makefile            |
c (43%)  42k of  58k [1] /usr2/src/stud/stud_main.o  <------+
c (54%)  20k of  78k [1] /usr2/src/stud/stud_main.c

/////////////////////////////////////////////////////////////////////////////


The output of the "error_check" ( bru -i -f /dev/mt/tps0d3nrv > /tmp/bru_errors
shows no errors BUT a look at SYSLOG shows there's been a "blocksize mismatch:

Jul 26 06:55:59 ricky unix: NOTICE: SCSI tape #3 blocksize mismatch; blocksize on tape is 20480 bytes
Jul 26 06:55:59 ricky unix: NOTICE: SCSI tape #3 blocksize mismatch; blocksize on tape is 20480 bytes 

What sorts of problems could lead to this error -- bad DAT,
bad cable, dirty heads, bad tape, all of the above?

Thanks.

-- 
"Is this the party to   |  David M. Senseman  (senseman@lonestar.utsa.edu)
 whom I am speaking?"   |  Brain Research Laboratory
          --Ernestine   |  The University of Texas at San Antonio
Newsgroups: comp.sys.sgi