From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Webb Subject: Re: MD/RAID time out writing superblock Date: Fri, 18 Sep 2009 18:07:42 +0100 Message-ID: <20090918170742.GJ2141@arachsys.com> References: <20090917115728.GA13854@arachsys.com> <4AB2596D.10809@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <4AB2596D.10809@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: Tejun Heo Cc: Neil Brown , Ric Wheeler , Andrei Tanas , linux-kernel@vger.kernel.org, IDE/ATA development list , linux-scsi@vger.kernel.org, Jeff Garzik , Mark Lord List-Id: linux-ide@vger.kernel.org Tejun Heo writes: > Chris Webb wrote: > > > Would such very slow (but ultimately successful) flushes be > > consistent with the theory of power supply issues affecting the > > drives? It feels like the 30s timeouts on flush could be just a more > > severe version of the 15s very slow flushes. > > Probably not. Power problems usually don't resolve themselves with > longer timeout. If the drive genuinely takes longer than 30s to > flush, it would be very interesting tho. That's something people have > been worrying about but hasn't materialized yet. The timeout is > controlled by SD_TIMEOUT in drivers/scsi/sd.h. You might want to bump > it up to, say, 60s and see whether anything changes. I'll add that to the list of things to check out on the test machine with a more disposable installation on it! The 15s flushes we're seeing on superblock barrier writes do already feel dangerously close to the 30s hardcoded timeout to me: it's only a factor of two. Cheers, Chris.