From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Schinagl Subject: Re: Small short question Was: Re: Recovering from the kernel bug, Neil? Date: Thu, 20 Sep 2012 19:05:33 +0200 Message-ID: <505B4CDD.7010509@schinagl.nl> References: <5030F07F.7000303@schinagl.nl> <504CFA7B.7090606@schinagl.nl> <20120910090829.19100cdf@notabene.brown> <504DA85C.6080000@schinagl.nl> <20120911161622.0b0fcf8c@notabene.brown> <505301E1.10707@schinagl.nl> <50531A52.7060205@schinagl.nl> <20120920122218.07f89443@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120920122218.07f89443@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: NeilBrown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 20-09-12 04:22, NeilBrown wrote: > On Fri, 14 Sep 2012 13:51:46 +0200 Oliver Schinagl > wrote: > >> Since I had only one valid device to check with etc, I assume that if >> fsck -n -f /dev/md2 runs sucessfully, it is 100% safe to assume the >> array is perfectly healthy? > I might be a bit late here but.... > > No, not 100% safe. > I would at least mount the filesystem and have a look around - take a random > sample and see if it all looks credible. If it does then that is as good as > it gets. I did check the FS, I ran some fsck tests and checked data on the drive, everything appeared to be normal. I still have to verify some unimportant iso images, once that is done, I cannot imagine the data being bad. > >> E.g. it should be perfectly safe to mdadm --zero-superblock on /dev/sda6 >> and add it to /dev/md2 (missing /dev/sdb6)? >> >> I know technically this all works out fine, and the bug shouldn't have >> broken anything in that regard. Or is it absolutly recommended to simply >> create a new array, with a new FS on it, and copy all data over >> (Logically also with /dev/md2, /dev/sda6 missing and later adding sdb6)? > Creating a new array shouldn't be necessary. In general I would avoid > copying data when convenient. I didn't think it would have mattered. The meta-data is rewritten so if data is good, everything is good. Since I added an empty disk to the 'half' array, everything is re-synced and a-ok. > NeilBrown