From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wido den Hollander Subject: Re: Is Ceph recovery able to handle massive crash Date: Tue, 08 Jan 2013 14:36:48 +0100 Message-ID: <50EC20F0.1060502@widodh.nl> References: <50E81A3D.5070100@ledeuns.net> <50EB0518.9050304@ledeuns.net> <50EBDC5E.3090207@ledeuns.net> <50EC17A6.1080707@ledeuns.net> <50EC1AC2.2060001@widodh.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp02.mail.pcextreme.nl ([109.72.87.138]:50065 "EHLO smtp02.mail.pcextreme.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754754Ab3AHNgv (ORCPT ); Tue, 8 Jan 2013 08:36:51 -0500 In-Reply-To: <50EC1AC2.2060001@widodh.nl> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Denis Fondras Cc: "ceph-devel@vger.kernel.org" On 01/08/2013 02:10 PM, Wido den Hollander wrote: > On 01/08/2013 01:57 PM, Denis Fondras wrote: >> Hello, >> >> I'm wondering if I can get every "rb.0.8e10.3e2219d7.*" from the OSD >> drive and cat them together and get back a usable raw volume from which >> I could get back my data ? >> > > Yes, that is doable. The problem only is that RBD is sparse. So you'd > have to fill up the empty spaces with 4MB of zeroes. > > But yes, it's doable if you gather all the objects and will the rest up > with zeroes. > >> Everything seems to be there but I don't know the order of the rbd >> objects. Are the last bytes of the file name the offset of the block ? >> > > There was a quick perl command for this to generate all the suffixes, > but I can't seem to find it right now. > You could do something like this to generate all the blocks you should need, the non-existing ones you should fill them with nothing, aka 4MB of nothing. perl -e 'while ($s < (SIZE_IN_MB / 4)) { printf "BLOCK_PREFIX.%012x\n", $s; $s++}' Size is the block-device in MB en BLOCK_PREFIX can be something like "rb.0.1016.238e1f29" Wido > Wido > >> Regards, >> Denis >> -- >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html