From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Greaves Subject: Re: questions about softraid limitations Date: Sun, 18 May 2008 10:11:55 +0100 Message-ID: <482FF2DB.9060604@dgreaves.com> References: <002801c8b55a$60e4a360$0404a8c0@dcccs> <482AC2BB.5010602@dgreaves.com> <01be01c8b61a$6e616260$9300a8c0@dcccs> <482D479F.3040809@dgreaves.com> <022401c8b739$5262ba80$9300a8c0@dcccs> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-2 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <022401c8b739$5262ba80$9300a8c0@dcccs> Sender: linux-raid-owner@vger.kernel.org To: Janos Haar Cc: linux-raid@vger.kernel.org, David Lethe List-Id: linux-raid.ids Janos Haar wrote: > At this time, i working in my data recovery company, and some times need Ah - I missed this too. > to recover the broken hw raid arrays too. > (with md arrays, we have no problem at all. :-) ) Nice quote for "the benefits of software raid" somewhere :) > In your rows, we talking about 2 cases: > > a, disk hw problem (only bad sectors, the completely failed disk is in > 'b' case) > Yes, the ddrescue is the best way, to do the recovery, but: > The ddrescue is too agressive with default -e 0 setting! > This can be easily fail down the drive! (dependig the reason of the bad > sectors) OK, worth knowing - what would you suggest? > And with the images, we have another problem! > The 0x00 holes. > The hw or md have no deal about where we need recover from parity and > where we have real zero blocks.... > Overall this is why data recovery companys learning and developing more > and more.... :-) Hmm - I wonder if things like ddrescue could work with the md bitmaps to improve this situation? Is this related to David Lethe's recent request? > I need no help at this time, i just want to share my ideas, to helping > upgrading/developing md, and helping for people.... OK - ta. David