From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id n1D0eLcR095848 for ; Thu, 12 Feb 2009 18:40:21 -0600 Received: from mx2.redhat.com (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 5FCE1192A5E6 for ; Thu, 12 Feb 2009 16:39:45 -0800 (PST) Received: from mx2.redhat.com (mx2.redhat.com [66.187.237.31]) by cuda.sgi.com with ESMTP id GW6eK4v9Nb8dv7HV for ; Thu, 12 Feb 2009 16:39:45 -0800 (PST) Message-ID: <4994C14E.5090402@sandeen.net> Date: Thu, 12 Feb 2009 18:39:42 -0600 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: Does XFS support the sync mount option? References: <884979c90902050643m78d2e0dbt85aa7f4369e243ef@mail.gmail.com> <20090206230502.GQ24173@disturbed> <884979c90902121546g35f594b1s592859ac7b832533@mail.gmail.com> In-Reply-To: <884979c90902121546g35f594b1s592859ac7b832533@mail.gmail.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Ewan Chalmers Cc: xfs@oss.sgi.com Ewan Chalmers wrote: > Thanks for your detailed reply. > >> And "sync" only works if you turn drive write caches off or have >> barriers enabled. There are many people out there that have systems >> that are suseptible to fatal filesystem corruption that could be >> triggered by doing this (because critical metadata is lost from >> the volatile write cache on the drive when you power it off). > > According to the FAQ, barriers are enabled by default since 2.6.17. That's kernel version > I > have 2.9.8, that's xfsprogs version. > so I guess barriers are enabled. I have checked and dmesg > contains no errors relating to barriers. > > Also according the FAQ... "With a single hard disk and barriers turned > on (on=default), the drive write cache is flushed before an after a > barrier is issued. A powerfail "only" loses data in the cache but no > essential ordering is violated, and corruption will not occur." > > So it sounds like pulling the plug on the disk should not cause > corruption in this case (sync mount and barriers default enabled). Or > am I just plain wrong? It should not cause metadata corruption > (BTW, I've done an xfs_repair which reported no errors.) ... which is what repair will check for. -Eric > Thanks, > Ewan _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs