From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754216Ab3KGKyH (ORCPT ); Thu, 7 Nov 2013 05:54:07 -0500 Received: from mail-wg0-f49.google.com ([74.125.82.49]:55197 "EHLO mail-wg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752456Ab3KGKyE (ORCPT ); Thu, 7 Nov 2013 05:54:04 -0500 MIME-Version: 1.0 X-Originating-IP: [72.21.198.64] In-Reply-To: <000f01ced948$2fbab140$8f3013c0$@lucidpixels.com> References: <000f01ced948$2fbab140$8f3013c0$@lucidpixels.com> Date: Thu, 7 Nov 2013 05:54:01 -0500 Message-ID: Subject: Re: 3.12: raid-1 mismatch_cnt question From: Justin Piszcz To: open list , linux-raid@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 4, 2013 at 5:25 AM, Justin Piszcz wrote: > Hi, > > I run two SSDs in a RAID-1 configuration and I have a swap partition on a > third SSD. Over time, the mismatch_cnt between the two devices grows higher > and higher. > > Once a week, I run a check and repair against the md devices to help bring > the mismatch_cnt down. When I run the check and repair, the system is live > so there are various logs/processes writing to disk. The system also has > ECC memory and there are no errors reported. > > The following graph is the mismatch_cnt from June 2013 to current; each drop > represents a check+repair. In September, I dropped the kernel/vm caches > before running check/repair and that seemed to help a bit. > http://home.comcast.net/~jpiszcz/20131104/md_raid_mismatch_cnt.png > > My question is: is this normal or should the mismatch_cnt always be 0 unless > there is a HW or md/driver issue? > > Justin. > Hi, Could anyone please comment if this is normal/expected behavior? Thanks, Justin.