On Fri, Aug 31, 2012 at 09:53:07AM +0100, Brian Candler wrote:
You're quite right: yesterday I did see some I/O errors after I had mounted
the filesystem using -o ro,noload.
So this morning I ran
dd if=/dev/sda8 of=/dev/null bs=1024k
and it completed without a problem. And then I found I was able to mount the
filesystem just fine!
So this is definitely a hardware problem; it's just I didn't realise I/O
errors could cause kernel panics as well as EIO.
Well, it's not *supposed* to cause kernel panics. If you can get a
stack trace in the future under similar circumstnaces, definitely
capture it (using a digital camera if you don't have a better way,
such as a network console or a serial console). Even if it's not an
ext4 bug, but I'm happy to to try to route the bug report to the
appropriate kernel developer or mailing list.
I am currently refreshing my most recent backup of this drive, and I'll
replace it ASAP.
The drive *might* be OK at this point. If you are willing to run a
full read/write test on the drive, and it shows no problem, it might
be worth trying to put it back in production (especially if you are
keeping regular backups); if it fails a second time, then it's
definitely time to replace it. It's really a question of how much the
cost of a new drive is worth compared to your time and the value of
your data in case of a second failure.
Or maybe you could a buy a second 500G drive, and set up software RAID
1 using the md device. This will give you protection if either of the
two drive fails, as well as giving you speed boost for reads.
Cheers!
- Ted