From mboxrd@z Thu Jan 1 00:00:00 1970 From: Piergiorgio Sartor Subject: Re: Problems with RAID 6 across 15 disks Date: Fri, 2 Apr 2010 01:04:37 +0200 Message-ID: <20100401230437.GA5067@lazy.lzy> References: <4BB49E4D.1090809@maxeaves.co.uk> <4BB4A461.5030704@redhat.com> <4BB4A89F.7030707@maxeaves.co.uk> <20100402074325.3ce34e8f@notabene.brown> <20100401224644.GA2455@lazy.lzy> <1270162736.24051.0.camel@travelmate.workshop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1270162736.24051.0.camel@travelmate.workshop> Sender: linux-raid-owner@vger.kernel.org To: Jools Wills Cc: Piergiorgio Sartor , Neil Brown , max@maxeaves.co.uk, linux-raid@vger.kernel.org, Doug Ledford List-Id: linux-raid.ids Hi, > > but since it is not possible to correct those errors, > > there is no point in doing it... :-) > > Well it can. It can try and rewrite the block based on the data from the > other disks, and if the drive needs to, it can remap the bad block. you might be unaware of the repeated neverending discussions about this topic. It is *possible* to do it, but, as of today, it cannot do it. I mean, there is no functionality, in the RAID-6, to detect and correct those errors using the available double parity. Consider that the RAID check returns only how many mismatch are present, not where they are, i.e. on which disks. bye, -- piergiorgio