atom feed70 messages in org.freebsd.freebsd-scsiSCSI tape data loss
FromSent OnAttachments
Kern SibbaldJun 1, 2003 10:54 am 
Dan LangilleJun 1, 2003 11:32 am 
Justin T. GibbsJun 1, 2003 1:08 pm 
Kern SibbaldJun 1, 2003 2:44 pm 
Justin T. GibbsJun 1, 2003 3:39 pm 
Matthew JacobJun 1, 2003 5:00 pm 
Matthew JacobJun 1, 2003 5:13 pm 
Dan LangilleJun 1, 2003 6:58 pm 
Matthew JacobJun 1, 2003 7:03 pm 
Kern SibbaldJun 2, 2003 1:28 am 
Kern SibbaldJun 2, 2003 1:29 am 
Kern SibbaldJun 2, 2003 1:57 am 
Kern SibbaldJun 2, 2003 3:45 am 
Dan LangilleJun 2, 2003 4:28 am 
Matthew JacobJun 2, 2003 8:05 am 
Justin T. GibbsJun 2, 2003 8:10 am 
Dan LangilleJun 2, 2003 8:14 am 
Matthew JacobJun 2, 2003 8:21 am 
Kern SibbaldJun 2, 2003 8:27 am 
Dan LangilleJun 2, 2003 9:46 am 
Dan LangilleJun 2, 2003 11:05 am 
Matthew JacobJun 2, 2003 11:11 am 
Justin T. GibbsJun 2, 2003 11:49 am 
Dan LangilleJun 2, 2003 12:06 pm 
Justin T. GibbsJun 2, 2003 12:10 pm 
Matthew JacobJun 2, 2003 1:14 pm 
Dan LangilleJun 2, 2003 2:16 pm 
Matthew JacobJun 2, 2003 2:24 pm 
Kern SibbaldJun 2, 2003 2:46 pm 
Matthew JacobJun 2, 2003 2:55 pm 
Kern SibbaldJun 2, 2003 3:31 pm 
Carl ReisingerJun 2, 2003 3:44 pm 
Matthew JacobJun 2, 2003 3:44 pm 
Dan LangilleJun 2, 2003 6:37 pm 
Kern SibbaldJun 3, 2003 12:28 am 
Kern SibbaldJun 3, 2003 6:07 am 
Carl ReisingerJun 3, 2003 6:19 am 
Kern SibbaldJun 3, 2003 6:37 am 
Carl ReisingerJun 3, 2003 7:01 am 
Matthew JacobJun 3, 2003 7:34 am 
Justin T. GibbsJun 3, 2003 7:51 am 
Kern SibbaldJun 3, 2003 8:05 am 
Kern SibbaldJun 3, 2003 8:11 am 
Matthew JacobJun 3, 2003 9:03 am 
Dan LangilleJun 3, 2003 9:10 am 
Justin T. GibbsJun 3, 2003 9:24 am 
Kern SibbaldJun 3, 2003 9:40 am 
Justin T. GibbsJun 3, 2003 10:03 am 
Kern SibbaldJun 3, 2003 10:19 am 
Kern SibbaldJun 3, 2003 10:34 am 
Matthew JacobJun 3, 2003 11:00 am 
Matthew JacobJun 3, 2003 11:16 am 
Matthew JacobJun 3, 2003 11:39 am 
Justin T. GibbsJun 3, 2003 12:12 pm 
Dan LangilleJun 3, 2003 12:43 pm 
Matthew JacobJun 3, 2003 12:46 pm 
Kern SibbaldJun 3, 2003 1:05 pm 
PostMaster GeneralJun 3, 2003 2:21 pm 
Kern SibbaldJun 4, 2003 12:20 am 
Matthew JacobJun 4, 2003 7:51 am 
Kern SibbaldJun 4, 2003 9:51 am 
Kern SibbaldJun 6, 2003 7:38 am 
Dan LangilleJun 6, 2003 8:59 am 
Matthew JacobJun 6, 2003 11:50 am 
Dan LangilleJun 20, 2003 6:17 pm 
Dan LangilleJul 1, 2003 5:07 pm 
Matthew JacobJul 1, 2003 11:11 pm 
Michael L. SquiresAug 25, 2003 4:16 am 
Dan LangilleAug 25, 2003 9:13 am 
Michael L. SquiresAug 27, 2003 5:27 am 
Subject:SCSI tape data loss
From:Matthew Jacob (mja@feral.com)
Date:Jun 3, 2003 7:34:33 am
List:org.freebsd.freebsd-scsi

The fact that you're getting ENOSPC means that you're getting to PEOT- past LEOT. I guess I need to see the Bacula source to see why LEOT is being missed. If you can build a kernel with CAMDEBUG and run

camcontrol debug -I b:t:l

(bus:target:lun for the tape) and rerun the test, you'll get boatloads of output, but an audit trail of what sastart and saerror are doing around the PEOT timeframe.

There's other stuff here that I need to collect my thoughts on to mail about. This will happen later today.

On Tue, 3 Jun 2003, Kern Sibbald wrote:

Hello,

Dan has now re-run our test of writing to two tapes. In this test, he told Bacula not to attempt to re-read the last block written, so Bacula wrote until -1 with errno=ENOSPC was returned, wrote two EOF marks then put up the next volume.

The results were the same (more or less) 12 blocks of data were lost, which corresponds to the smaller size of the restored file that was split across two tapes.

These 12 blocks were also at the end of the tape.

During the restore, Bacula reported the following:

03-Jun-2003 05:01 undef-sd: RestoreFiles.2003-06-03_04.36.59 Error: Invalid block number. Expected 6060, got 6072

and in Bacula's database, Bacula indicates that blocks 0 to 6072 were written to the first tape. In fact, only blocks 0 to 6071 were written to the first tape -- I see that Bacula has included the failed block in its count, which is wrong, but this doesn't change the results at all though.

Bottom line:

Even when we eliminate the code that backs up and re-reads the last block, we still see the last 12 or 13 blocks being lost. They were written by the program but are not physically on the tape.

Next step:

Dan is now running a test where Bacula will stop writing on the first tape before the EOM is reached.

Best regards,

Kern