From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joao Eduardo Luis Subject: Re: ceph replication and data redundancy Date: Mon, 21 Jan 2013 13:08:42 +0000 Message-ID: <50FD3DDA.6060502@inktank.com> References: <50FC2967.6080207@widodh.nl> <48C16807A78A464DA590FC8010B37632@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-la0-f54.google.com ([209.85.215.54]:48838 "EHLO mail-la0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752736Ab3AUNIw (ORCPT ); Mon, 21 Jan 2013 08:08:52 -0500 Received: by mail-la0-f54.google.com with SMTP id gw10so5191373lab.41 for ; Mon, 21 Jan 2013 05:08:51 -0800 (PST) In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Ulysse 31 Cc: Gregory Farnum , Wido den Hollander , ceph-devel@vger.kernel.org On 01/21/2013 08:14 AM, Ulysse 31 wrote: > Hi everybody, > > In fact, i found searching the doc on section "adding/removing a > monitor", infos about the paxos system used for quorum establishment. > Following the documentation, in a catastrophy scenario, i need to > remove the other monitors configured on the other buildings. > For better efficiency, i think i'll keep 1 monitor per building, and, > if two other building fails, i will delete those two monitors from the > configuration in order to access data again. > I'll simulate that and see if it goes well. > Thanks for your help and advices. If you are set on that approach, you could just as well add a third monitor on one of the buildings (whichever you feel to be more resilient), and cut down the chances of an unavailable cluster if the other fails. It doesn't solve your problem, but if the building with just one monitor fails, your cluster will still be available; if it's the other way around, you could do the manual recovery just the same anyway. -Joao