From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: hdaprm -Y /dev/sda /dev/sdb -> I/O error -> disk kicked out of RAID - is it normal? Date: Fri, 17 Jul 2009 13:48:44 +0900 Message-ID: <4A6002AC.9090807@kernel.org> References: <4A5FB1DD.3000904@wpkg.org> <4A5FFA46.1070203@kernel.org> <29d09dacb3dce47830a95bc6493d3b88.squirrel@neil.brown.name> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <29d09dacb3dce47830a95bc6493d3b88.squirrel@neil.brown.name> Sender: linux-raid-owner@vger.kernel.org To: NeilBrown Cc: Tomasz Chmielewski , linux-raid@vger.kernel.org, linux-ide@vger.kernel.org List-Id: linux-raid.ids NeilBrown wrote: > On Fri, July 17, 2009 2:12 pm, Tejun Heo wrote: >> Tomasz Chmielewski wrote: >>> And one of the disks is kicked out of RAID. >>> >>> Is it expected behaviour (although probably the error happens somewhere >>> in the ata layer)? >> Yes, it's expected. Wakeup requires reset via EH and md requests have >> FAILFAST flag set, so they never get retried. The behavior can be >> changed tho. Hmmm... not entirely sure what to do at this point. > > Nope, 'md' requests do not get FAILFAST set. Oh... then it's unexpected. I'll see if I can reproduce the failure here. > I tried that and easily found cases where it fails way too fast. > FAILFAST seems to mean different things on different devices, making > it useless in general (it is still useful in some specific cases > such as multipath on devices which are expected to be used under > multipath and so treat FAILFAST appropriately). Yeap, FAILFAST flags seem geared pretty much toward multipathing. Thanks. -- tejun