Geert, I believe you have described the symptoms precisely. Yes, I do have a linux system. I will insert here some kernel log file excerpts to demonstrate more precisely the symptoms. This is another bug in this particular driver (aic79xx scsi) that needs reporting I suppose. Note taht scsi id=6 is the tape drive and the first device to show an error. This happened again last night so perhaps it is more than just a dirty tape drive. Friday after noon (last backup), an entire backup completed without an error.
Apr 16 01:24:08 fea8 kernel: (scsi0:0:6:0) Data overrun detected in Data-Out phase, tag 0; Apr 16 01:24:08 fea8 kernel: Have seen Data Phase. Length=0, NumSGs=0. Apr 16 01:24:08 fea8 kernel: Raw SCSI Command: 0x0a 01 00 00 20 00 Apr 16 01:24:08 fea8 kernel: st0: Error 70000 (sugg. bt 0x0, driver bt 0x0, host bt 0x7). Apr 16 01:24:09 fea8 kernel: PCI-DMA: Out of IOMMU space for 36864 bytes at device 0000:03:05.0 Apr 16 01:24:09 fea8 kernel: ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 Apr 16 01:24:09 fea8 kernel: ata2.00: cmd 35/00:00:05:85:10/00:04:1b:00:00/e0 tag 0 cdb 0x0 data 524288 out Apr 16 01:24:09 fea8 kernel: res 50/00:00:86:0b:70/00:00:00:00:00/e2 Emask 0x40 (internal error) Apr 16 01:24:09 fea8 kernel: ata2.00: configured for UDMA/100 Apr 16 01:24:09 fea8 kernel: ata2: EH complete Apr 16 01:24:09 fea8 kernel: PCI-DMA: Out of IOMMU space for 36864 bytes at device 0000:03:05.0 Apr 16 01:24:09 fea8 kernel: ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 Apr 16 01:24:09 fea8 kernel: ata2.00: cmd 35/00:00:05:85:10/00:04:1b:00:00/e0 tag 0 cdb 0x0 data 524288 out Apr 16 01:24:09 fea8 kernel: res 50/00:44:00:01:80/00:00:00:00:00/a0 Emask 0x40 (internal error) Apr 16 01:24:09 fea8 kernel: ata2.00: configured for UDMA/100 Apr 16 01:24:09 fea8 kernel: ata2: EH complete Apr 16 01:24:09 fea8 kernel: PCI-DMA: Out of IOMMU space for 36864 bytes at device 0000:03:05.0 Apr 16 01:24:09 fea8 kernel: ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 Apr 16 01:24:09 fea8 kernel: ata2.00: cmd 35/00:00:05:85:10/00:04:1b:00:00/e0 tag 0 cdb 0x0 data 524288 out Apr 16 01:24:09 fea8 kernel: res 50/00:44:00:01:80/03:00:00:00:00/a0 Emask 0x40 (internal error) Apr 16 01:24:09 fea8 kernel: ata2.00: configured for UDMA/100 Apr 16 01:24:09 fea8 kernel: ata2: EH complete - On Sat, 2007-04-14 at 16:28 +0200, Geert Uytterhoeven wrote: > On Fri, 13 Apr 2007, Freels, James D. wrote: > > I discovered today that my tape drive was dirty and did not realize it. > > What happened was the drive sent a scsi error to the kernel/OS and > > somehow the root (/), home (/home), and holding disk area recognized by > > AMANDA was changed from rw access to ro access. I believe this change > > was made by AMANDA itself. This happened while AMANDA was backing up. > > > > I had to reboot the machine to place the ro filesystems back to rw as > > they should be. I then repeated the attempted backup and the failure > > occurred again exactly the same way (so it was repeatable). This is > > when I suspected the dirty tape drive. I cleaned the drive and the > > problem went away. The backups now work like they should (and have for > > years). > > > > This is the first time I have seen this. The drive got dirty due to a > > different person changing the tapes did not realize they should also > > clean the drive occasionally. I also have new higher-capacity tapes so > > that the same number of tapes will get the driver dirtier quicker. > > > > Does the switch from rw to ro by AMANDA make sense ?? Is this a > > "feature" ? This is first I have heard of this. > > The Linux kernel (I assume you run Linux?) automatically remounts a file > system ro if it notices a medium error on the underlying disk. > > Since there are no actual medium errors on the disk, but problems on the > tape drive (both are on the same SCSI host adapter?), it looks like the SCSI > driver has a bug and incorrectly told the upper layer about an error on > the disk. Is there some more info about the actual error(s) in the kernel > logs? > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [EMAIL PROTECTED] > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like > that. > -- Linus Torvalds -- James D. Freels, Ph.D. Oak Ridge National Laboratory [EMAIL PROTECTED] "Windmills can't even produce enough energy to manufacture a windmill." -Ann Coulter, 03/01/07.