From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wido den Hollander Subject: Re: ceph replication and data redundancy Date: Mon, 21 Jan 2013 14:40:50 +0100 Message-ID: <50FD4562.3070605@widodh.nl> References: <50FC2967.6080207@widodh.nl> <48C16807A78A464DA590FC8010B37632@inktank.com> <50FD3DDA.6060502@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp01.mail.pcextreme.nl ([109.72.87.137]:53964 "EHLO smtp01.mail.pcextreme.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752335Ab3AUNkw (ORCPT ); Mon, 21 Jan 2013 08:40:52 -0500 In-Reply-To: <50FD3DDA.6060502@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Joao Eduardo Luis Cc: Ulysse 31 , Gregory Farnum , ceph-devel@vger.kernel.org On 01/21/2013 02:08 PM, Joao Eduardo Luis wrote: > 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. > Another approach, if possible try to add a 3rd monitor in a "neutral" place. I for sure don't know how your network looks like, but you might be able to put up a monitor in an external datacenter and do something with a VPN? Assuming both buildings have their own external internet connection. Wido > -Joao >