Re: ZFS data error without reasons

On Mon, 30 Mar 2009, Thomas Sparrevohn wrote:

> On Wednesday 25 March 2009 09:41:39 kevin wrote:
>> Mark Powell wrote:
>>> Kevin,
>>> Did you fix your ZFS CRC errors?
>>> I responded to your thread, but no-one got back to me.
>>> I'm gonna start another thread later.
>>> This time I re-made the zpool in 8 compatible with 7. Once the errors
>>> started showing up in 8 I moved back to 7, on the same hardware, to
>>> perform the scrub to prove the problem is with 8. The 1st scrub in 7
>>> found some errors, but of course it would if 8 had messed up the data.
>>> Removed the few unimportant bad files (all were in snapshots).
>>> Just performing the 2nd scrub in 7 now. If this comes back with no
>>> errors, then we have stronger proof that there is some wrong, which
>>> seems quite intermittent, in 8 that randomly writes bad data.
>>> Cheers.
>>>
>> Yes，I can fix some ZFS CRC errors,and sometimes i can recover all error
>> files.Before i run "zpool import backup" to mount the zpool on a usb
>> hard disk, "zpool status" return no errors. When i copy files to the usb
>> hard disk,soon I can get lots of file errors.After a reboot,if i run
>> scrub,i can fix many errors. I just think copy files between two zpools,
>> one is on local hard disk and the other one is on a usb hard disk, may
>> easily reproduce the bug.

I didn't write that!

> I have not been folloing the entire thread - but I can reproduce ZFS CRC 
> corruption on the current kernel just by unpluging a USB disk drive - 
> The is no errors on the disks - revert to and old kernel FreeBSD 
> w2fzz0vc03.aah-go-on.com 8.0-CURRENT FreeBSD 8.0-CURRENT #1 r189454M: 
> Fri Mar 6 18:46:25 GMT 2009 
> root_at_w2fzz0vc03.aah-go-on.com:/usr/obj/usr/src/sys/GENERIC amd64
>
> the problem can be solved - The weird thing is that it will give CRC 
> errros (and permenent errors) in blocks that has not been touched (or at 
> least I think so)

Can you be a little clearer? Perhaps some zpool status output with the 
steps you've taken?

> I suspect that It may have to do with the USB DMA bounce buffer as an 
> example see the message file included

I expect this is a red hering, but do you not have some kind of 
kernel/module sync problem?

Mar 26 13:48:18 w2fzz0vc03 root: /etc/rc: WARNING: Unable to load kernel module daemon_saver
Mar 26 13:48:18 w2fzz0vc03 kernel: KLD daemon_saver.ko: depends on kernel - not available

   Cheers.

-- 
Mark Powell - UNIX System Administrator - The University of Salford
Information & Learning Services, Clifford Whitworth Building,
Salford University, Manchester, M5 4WT, UK.
Tel: +44 161 295 6843  Fax: +44 161 295 5888  www.pgp.com for PGP key