Re: [OT] scsi tape problems

[Lars Knudsen <gandalf@revicon.com>]

Martin Würtele wrote:
> 
> hi,
> 
> i have a problem with my scsi tape (HP C1537A DDS3):
> 
> the scsi ids are set as follows:
> Host: scsi0 Channel: 00 Id: 00 Lun: 00
>   Vendor: IBM      Model: DNES-318350Y     Rev: SA30
>   Type:   Direct-Access                    ANSI SCSI revision: 03
> Host: scsi0 Channel: 00 Id: 01 Lun: 00
>   Vendor: IBM      Model: DNES-318350Y     Rev: SA30
>   Type:   Direct-Access                    ANSI SCSI revision: 03
> Host: scsi0 Channel: 00 Id: 03 Lun: 00
>   Vendor: HP       Model: C1537A           Rev: L907
>   Type:   Sequential-Access                ANSI SCSI revision: 02
> inetmain:/etc/afbackup#
> 
> and mt -f /dev/nst0 stat reports
> drive type = Generic SCSI-2 tape
> drive status = 620756992
> sense key error = 0
> residue count = 0
> file number = 54
> block number = 0
> Tape block size 0 bytes. Density code 0x25 (unknown).
> Soft error count since last status=0
> General status bits on (89010000):
>  EOF EOD ONLINE IM_REP_EN
> 
> but when i start afbackup the server always reports:
> mt: /dev/nst0: Input/output error
> 
> but it dows increase the file nr and if i kill it (i know i never should but
> as i can't be shure the backup is written...) i see eg
> drive type = Generic SCSI-2 tape
> drive status = 620756992
> sense key error = 0
> residue count = 0
> file number = 54
> block number = 0
> Tape block size 0 bytes. Density code 0x25 (unknown).
> Soft error count since last status=0
> General status bits on (89010000):
>  EOF EOD ONLINE IM_REP_EN
> 
> and  mt -f /dev/nst0 rewind works as well.
> 
> what problem could this be? before changing to the DDS 3 tape drive
> the DDS 2 drive worked fine.
> 
> any ideas?
> 

You might want to try to isolate the problem a bit to see if 
the problem has to do with the backup software. A simple way
to check this would be to use tar to write and subsequently
read back a small backup.

Something like:
tar cvf /dev/st0 dir_you_want_to_backup

should write the backup to the tape and:
tar df /dev/st0

should read the tape and perform a diff with the files on
disk. If everything is ok no output should be generated.

Happy hacking,

\Gandalf