From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Fjellstrom Subject: Re: Re-add not selecting drive for correct slot? Date: Mon, 10 Aug 2015 11:44:20 -0600 Message-ID: <2248170.b8F2naoiGF@balsa> References: <1817382.9YhZ7ff5Yl@balsa> <1526790.RuPxcltSBQ@nell> Reply-To: thomas@fjellstrom.ca Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Mikael Abrahamsson Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Mon 10 Aug 2015 11:35:13 AM Mikael Abrahamsson wrote: > On Sat, 8 Aug 2015, Thomas Fjellstrom wrote: > > I did try that :( It fails to assemble because it only sees sdc as a > > spare. > > Maybe because I did things with the old mdadm first, and did a --remove? > > That seems to have wiped out the "slot" information (it's -1) so the > > assemble force magic can't figure things out? Just a guess on my part. > > Unless someone else has a better idea, I'd say you're right. If you would > have unplugged the failed drive (so it disappeared completely), it could > probably have been re-added. So unless you have a copy of the old > superblock, your only way to proceed now is to use --create --assume-clean > and get all the parameters right (order, offsets etc). There are lots of > examples in the mailing list archives of people trying this and some > actually suceeding. I think the only thing that would stop that from working is that there is data in the bitmap. So if a assume clean is done, it might ignore that and cause some extra corruption? It'd be interesting to figure out if i can set that slot number manually or with a tool. That might be a smarter/safer way of doing it. -- Thomas Fjellstrom thomas@fjellstrom.ca