Unexpected SU+J inconsistency AGAIN -- please, don't shift topic to ZFS!

Ivan Voras ivoras at freebsd.org
Thu Feb 28 14:19:59 UTC 2013

On 28/02/2013 11:31, Lev Serebryakov wrote:

>  WD disks are in software RAID5 with geom_raid5 (from ports, but I'm
>  active maintainer of it).
>    Disks are in "Default" configuration: WC and NCQ are enabled.
>    I know, that FS guys could blame geom_raid5, as it could delay real
>  write up to 15 seconds, but it never "lies" about writes (it doesn't
>  mark BIOs complete till they are really sent to disk) and I could
>  not reproduce any problems with it on many hours tests on VMs (and I
>  don't want to experiment a lot on real hardware, as it contains my
>  real data).
>    Maybe, it is subtile interference between raid5 implementation and
>   SU+J, but in such case I want to understand what does raid5 do
>   wrong.

You guessed correctly, I was going to blame geom_raid5 :)

Is this a production setup you have? Can you afford to destroy it and
re-create it for the purpose of testing, this time with geom_raid3
(which should be synchronous with respect to writes)?

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 260 bytes
Desc: OpenPGP digital signature
URL: <http://lists.freebsd.org/pipermail/freebsd-current/attachments/20130228/e8dfa625/attachment.sig>

More information about the freebsd-current mailing list