Re: Problem with dump on a DAT drive with 5.2.1 RELEASE.

From: John Sloan (john.sloanNOSPAM_at_NOSPAMrogers.com)
Date: 06/07/04 

Date: Mon, 07 Jun 2004 07:37:03 GMT

sam wrote:
> John Sloan wrote:
>> Rob wrote:
>>
>>> John Sloan wrote:
>>>
>>>
>>>> Hi, all. I have an odd problem using dump on 5.2.1 Release, with
an
>>>> HP SureStore DAT8 drive (SCSI DDS-2 drive):
>>
>>
>>> What tape device are you using? If you're not specifying a
>>
>> non-rewind
>>
>>> device then the above is what I'd expect.
>>
>>
>> Tape drive is an HP Surestore DAT8 drive. This is a DDS-2 DAT
drive,
>> with hardware compression available. Interface is SCSI. This drive
>> has no loader.
>>
>> "mt status" returns:
>>
>> freebsdbox# mt status
>> Mode Density Blocksize bpi Compression
>> Current: 0x24:DDS-2 variable 61000 DCLZ
>> ---------available modes---------
>> 0: 0x24:DDS-2 variable 61000 DCLZ
>> 1: 0x24:DDS-2 variable 61000 DCLZ
>> 2: 0x24:DDS-2 variable 61000 DCLZ
>> 3: 0x24:DDS-2 variable 61000 DCLZ
>> ---------------------------------
>> Current Driver State: at rest.
>> ---------------------------------
>> File Number: 0 Record Number: 0 Residual Count 0
>>
>> I'm not sure what you mean by "non-rewind device". I can tell the
>> drive to rewind the tape with the command "mt rewind" and it
>> successfully rewinds the tape.
>>
>> I have been using the default tape device for mt commands, which is
>> /dev/nsa0.
>> I have also been using the default device for dump commands, which
I
>> _believe_ is /dev/sa0
>>
>> Question: What is the difference between /dev/nsa0 and /dev/sa0?
>>
>> Thanks for your help!
>>
>> JS
>>
>>
>>
>>
> There is specific Jumper setup at the back of the storage. You can
> configure that Jumper to auto-rewind or non-auto-rewind.

Thanks for your help.

I figured it out: Because I was using the rewind device "sa0" and not
the non-rewind device "nsa0", I needed to use the "mt eod" command to
reposition the tape for the next dump. However, according to mtio(4),
there are two EOF markers written to the end of the tape after a dump,
and probably the "mt eod" command would set the tape head past the
last marker. So, each dump would have 2 EOF at the end, and that would
make the even-numbered dumps 0 length.

So I'm rerunning the backup now, using the non-rewind device
explicitly. Hopefully it will be all OK now.

JS

Relevant Pages

  • Re: Problem with dump on a DAT drive with 5.2.1 RELEASE.
    ... Tape drive is an HP Surestore DAT8 drive. ... drive to rewind the tape with the command "mt rewind" and it ... I have also been using the default device for dump commands, ...
    (comp.unix.bsd.freebsd.misc)
  • Problem with dump on a DAT drive with 5.2.1 RELEASE.
    ... I have an odd problem using dump on 5.2.1 Release, ... When I do multiple dumps to the same tape, I have to do a "mt eod" ... I can use the restore commands as follows: ...
    (comp.unix.bsd.freebsd.misc)
  • Multi-tape backup with "dump"
    ... dump wedges when I put in a new tape. ... as much cpu as they can, ... <ACPI PCI bus> on pcib0 ...
    (freebsd-questions)
  • ufsrestore not /dev/fd friendly
    ... I've recently begun keeping dump tapes' contents online. ... Verify tape and initialize maps ... Unfortunately, on Solaris, ufsrestore seems to incorrectly interpret ... resync restore, skipped 1 blocks ...
    (comp.unix.solaris)
  • Re: Dumping SMF directly to TAPE
    ... Actually our SMF dump job dumps to a daily tape which in the next step is mod on to a weekly tape using IEBGENER. ... This proc used the old IBM "SMFDUMP" program to dump all non-empty SMF datasets to DASD GDS. ...
    (bit.listserv.ibm-main)