From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Campbell Subject: Re: Huge values of mismatch_cnt on RAID 6 arrays under Fedora 18 Date: Mon, 28 Jan 2013 10:07:46 +0800 Message-ID: <5105DD72.6080909@fnarfbargle.com> References: <20130127192656.634892005AD@gemini.denx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130127192656.634892005AD@gemini.denx.de> Sender: linux-raid-owner@vger.kernel.org To: Wolfgang Denk Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 28/01/13 03:26, Wolfgang Denk wrote: > I have seen "mismatch_cnt is not 0" warnings in the past, but that has > always been with RAID 1 arrays, and with relatively small numbers on > /sys/block/md*/md/mismatch_cnt; my understanding was that this was not > actually critical. > > However, after updating to Fedora 18, I get this message from all > updated > systems that have RAID 6 arrays, and with _huge_ numbers of > mismatch_cnt, like that: I saw this when I put two drives from a 10 drive RAID6 on a sil3124 card. Unfortunately by the time I figured out what was going on my array was trashed. Massive mismatch counts are indicative of an insidious problem further down the storage stack. Check your drivers, cards, cables and PSU.