From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Dan Williams" Subject: Re: raid6 rebuild Date: Thu, 5 Apr 2007 09:59:10 -0700 Message-ID: References: <20070404194638.GB3712@xi.wantstofly.org> <20070405055030.GA6978@xi.wantstofly.org> <4614FF86.3020007@tmr.com> <20070405140626.GA8726@xi.wantstofly.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20070405140626.GA8726@xi.wantstofly.org> Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: Lennert Buytenhek Cc: Bill Davidsen , mingo@redhat.com, neilb@suse.de, linux-raid@vger.kernel.org List-Id: linux-raid.ids On 4/5/07, Lennert Buytenhek wrote: > On Thu, Apr 05, 2007 at 09:54:14AM -0400, Bill Davidsen wrote: > > > I confess, I would feel safer with my data if the rebuild started > > over, I would like to be sure that when it (finally) finishes the > > data are valid. > > With disk #3 about to die, I'd have felt safer if it first finished > rebuilding the replacement disk for failed disk #1 (that rebuild had > almost completed at that point), safeguarding the array against a > third disk failure. > I agree, the current arrangement seems to throw away a significant amount of work. Yes, you will need to resync when re-adding the second disk, but in the meantime might as well try to get a redundant mode at all costs. > Yeah, I know, you're not supposed to lose three disks within one day. > > > > If you replaced the 2nd drive, then a full rebuild would be required > > in any case, to get ALL drives valid. > > You could finish the last little bit of the resync of the replacement > for failed disk #1 (by looking at P+Q), and then re-sync the replacement > for failed disk #2 (by looking only at P..) > - -- Dan