From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wido den Hollander Subject: Re: Multiple disks per server. Date: Tue, 04 May 2010 14:34:26 +0200 Message-ID: <1272976466.1935.13.camel@wido-desktop> References: <4BE01091.7040103@embl.fr> Reply-To: wido@pcextreme.nl Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from support.pcextreme.nl ([89.18.190.50]:44589 "EHLO support.pcextreme.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752824Ab0EDMe3 (ORCPT ); Tue, 4 May 2010 08:34:29 -0400 In-Reply-To: <4BE01091.7040103@embl.fr> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: =?ISO-8859-1?Q?Micka=EBl_Can=E9vet?= Cc: ceph-devel@vger.kernel.org Hi Micka=C3=ABl, I was wondering the same. When i was reading the Wiki, i found: http://ceph.newdream.net/wiki/Librados "Each pool also has a few parameters that define how the object is stored, namely a replication level (2x, 3x, etc.) and a mapping rule describing how replicas should be distributed across the storage cluste= r (e.g., each replica in a separate rack)." So there should be a possibility, but i haven't found any configuration references. --=20 Met vriendelijke groet, Wido den Hollander Hoofd Systeembeheer / CSO Telefoon Support Nederland: 0900 9633 (45 cpm) Telefoon Support Belgi=C3=AB: 0900 70312 (45 cpm) Telefoon Direct: (+31) (0)20 50 60 104 =46ax: +31 (0)20 50 60 111 E-mail: support@pcextreme.nl Website: http://www.pcextreme.nl Kennisbank: http://support.pcextreme.nl/ Netwerkstatus: http://nmc.pcextreme.nl On Tue, 2010-05-04 at 12:18 +0000, Micka=C3=ABl Can=C3=A9vet wrote: > Hi, >=20 > I'm testing ceph on 4 old servers. >=20 > As there is more then one disk per server available for data (2 with = 6=20 > disks and 2 with 10 disks for a total of 32 disks over 4 nodes), I wa= s=20 > wondering how to define OSDs. >=20 > I have choice between one OSD per disk (32 OSDs on the cluster) or on= e=20 > OSD per server with one btrfs filesystem over all disks of the server= (4=20 > OSDs on the cluster). Which one is the best solution ? >=20 > In the first case, if I lose one disk, I lose only a small part of=20 > available space. In the other case, if I lose one disk, I lose the wh= ole=20 > server (as btrfs filesystem is in stripping) much more space. >=20 > On the other hand, if I lose the whole server in the first case, I ca= n=20 > lose all replicates of a data because they may be on two different OS= D=20 > on the same server. >=20 > Is there a way to define OSD groups so that we can be sure that 2=20 > replicates are not on OSDs of the same group (could be usefull for=20 > multiple OSDs per server, but also mutliple server per computing room= -=20 > if I lose one whole room, a lot of server, I will be sure that I have= =20 > not lost every replicates). >=20 > Thanks a lot. > Micka=C3=ABl > -- > 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" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html