Re: Help! zpool corrupted!

On Tue, 2009-03-03 at 00:45 +0300, Cache wrote:
> I have FreeBSD 8.0-CURRENT r188913M (amd64) on notebook with dual core
> Turion and 4G of RAM. Disk controller is AMD SB600. Single HDD -
> SATA-150 250G WD2500BEVS, ad4 at ata2, formatted with one ufs root
> partition 256M (ad4s1a) and ZFS pool (ver. 6 from FreeBSD 7-STABLE,
> ad4s1d) on rest of the disk. On ZFS pool I have about ten
> datasets: /root /usr /home /usr/src etc.
> 
> Now I have zpool status "One or more devices has experienced an
> error...". When I run scrubing, I see many errors in pool. Every scrub
> after reboot displays different amount of errors: 47, 176 - or ~24000.
> Disk and disk controller seems to be OK, checked with mhdd, but with
> hw.ata.ata_dma=1 there are error messages in console sometimes
> (something like 'DMA error'. Sorry, I can't explain its. I don't save
> its last time and now trying to reproduce).
> 
> When I set hw.ata.ata_dma=0 in loader.conf, there are no errors in
> console.
> 
> With 'zfs mount -a' command terminal not returns command prompt, but
> system not freezes - any typing echoed to display and ctrl-alt-del
> reboots system as expected. I tried to mound datasets manually -
> system became thinking on /home and /usr.
> 
> Does anybody know, how can I restore those two datasets or just make
> its temporary accessible for retrieving data? Any HOWTOs? I have some
> important data and many polished app configs on /home and just not
> want one more time installing of ~1000 ports... And yes, I stupid,
> because last backup was long time ago... :(

Can you reboot with your last kernel and see if that fixes things?
There was apparently a window where ATA drives could return data that
was corrupted - but the on-disk data was untouched.  This only happened
for particular controllers, but r188913 is inside the window where there
were problems.

If reverting the kernel fixes things for you, I believe you should be
fine just updating again to the code as of today.

Gavin