From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bryant Ng Subject: Crush and Monitor questions Date: Tue, 11 Dec 2012 12:23:54 -0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from plane.gmane.org ([80.91.229.3]:41766 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753176Ab2LKUY5 (ORCPT ); Tue, 11 Dec 2012 15:24:57 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1TiWNz-0005No-QH for ceph-devel@vger.kernel.org; Tue, 11 Dec 2012 21:25:03 +0100 Received: from 50-76-54-11-ip-static.hfc.comcastbusiness.net ([50.76.54.11]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 11 Dec 2012 21:25:03 +0100 Received: from bryantng by 50-76-54-11-ip-static.hfc.comcastbusiness.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 11 Dec 2012 21:25:03 +0100 Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel@vger.kernel.org Hi, I'm pretty new to Ceph and am just learning about it. Where are the CRUSH maps stored in Ceph? In the documentation I see you use the 'crushtool' to compile and decompile the crush map. I understand that if a single monitor comes online, it can talk to the other existing monitors to get the cluster map but how does it work on initial startup? Or if the entire Ceph clusters goes down b/c of power failure or something. What is the recommended hardware configuration for monitors? In the Hardware Recommendation page it says "A monitor requires approximately 10GB of storage space per daemon instance." per daemon instance is talking about the monitor daemon, not the osd daemons? Also further down on that page, it list some hardware examples where it mentions a ligher configuration for monitors. I am assuming that is the Dell PE R510 which contains 8 x 2 TB drives. Why does the monitor need so much space if it's "10GB of storage space per daemon instance". -Bryant