off topic - disk crash

[Christoph P. Kukulies]

On Sun, Mar 14, 2004 at 01:42:18PM +0100, Søren Schmidt wrote:
> Christoph P. Kukulies wrote:
> 
> >the whole image including partition table so that I will not have to
> >scan the disk for the start of the filesystems.
> 
> Dont get another DTLA/AVER IBM disk, you will just have the same problem 
> again sometime in the future, stay away from IBM/Hitachi disks that is 
> based on these models (I dont know much about the newer disks from 
> Hitachi and frankly I wont waste my money on them to find out).

Yes, I abandoned that idea now since things turn out a bit better.

I have built up a recovery system with a new big disk as a FreeBSD 5.2.1
and hooked the troubled disk as in as ad2.

I can mount -rf /dev/ad2s1g /mnt and find the old FS with all its
entries.

I copied over already some very important files and as it seems I will not
be as catastrophical as I initially thought.

With certain directories or files I get READ_DMA timeouts and also the system
hangs totally when a certain type of error occurs.

ad2: TIMEOUT - READ_DMA retryinmg (2 retries left) LBA=24703729
ad2: WARNING - READ_DMA Interrupt was seen but but timeout fired LBA=24703729 
ad2: WARNING - READ_DMA Interrupt was seen but but taskqueue stalled LBA=24703729 
ad0: FAILURE - WRITE_DMA status=51<READY,DSC,ERROR> error=40<UNCORRECTABLE> LBA=9825063

What I find strange is that the failing drive on the secondary IDE channel
causes the primary channel also to fail.

I wonder if this has to happen or could be avoided. I can only reboot from
that point on.

For recovering data this additionally painful and it would be nice I could
get this fixed somehow.

Another question is whether the read error occurs on the actual data
or only during the fstat or directory read. Is it possible to mount a 
FS with an alternate superblock as information base or do I have to fsck 
(write back to the disk risking that things get worse)

--
Chris Christoph P. U. Kukulies kuku_at_physik.rwth-aachen.de