From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bas van Schaik Subject: Re: Redundancy check using "echo check > sync_action": error reporting? Date: Thu, 20 Mar 2008 15:19:08 +0100 Message-ID: <47E2725C.1020206@tuxes.nl> References: <47DD2CD7.2090802@tuxes.nl> <20080316161451.0d17fd22@szpak> <47E26775.3000500@tuxes.nl> <20080320134747.GA28114@cthulhu.home.robinhill.me.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080320134747.GA28114@cthulhu.home.robinhill.me.uk> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org Cc: Theodore Tso List-Id: linux-raid.ids Robin Hill wrote: > On Thu Mar 20, 2008 at 02:32:37PM +0100, Bas van Schaik wrote: > >> Anyone able to answer the last and most important question: does it >> produce a message during resync in case of corruption? That would be great! >> > There's no explicit message produced by the md module, no. You need to > check the /sys/block/md{X}/md/mismatch_cnt entry to find out how many > mismatches there are. Similarly, following a repair this will indicate > how many mismatches it thinks have been fixed (by updating the parity > block to match the data blocks). > Marvellous! I naively assumed that the module would warn me, but that's not true. Wouldn't it be appropriate to print a message to dmesg if such a mismatch occurs during a check? Such a mismatch clearly means that there is something wrong with your hardware lying beneath md, doesn't it? > I've no idea whether the checkarray script you're using is checking this > counter - there seems little point in having a special script if it > isn't though. > If I understand the meaning of this counter, it would be sufficient to check the value of it _before_ the check operation and compare that value to the counter value _after_ the check. If the counter has increased: the check has encountered some inconsistencies which should be reported. Please correct me if I'm wrong! Cheers, Bas