From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Horner Subject: Re: Client Location Date: Wed, 10 Oct 2012 10:16:04 +0100 (BST) Message-ID: <653431320.70.1349860564219.JavaMail.root@corellia.pncl.co.uk> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from corellia.pncl.co.uk ([195.224.14.166]:45690 "EHLO corellia.pncl.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752291Ab2JJJQ0 convert rfc822-to-8bit (ORCPT ); Wed, 10 Oct 2012 05:16:26 -0400 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Gregory Farnum Cc: James Horner , ceph-devel@vger.kernel.org, Mark Kampe Hi There The basic setup Im trying to get is a backend to a Hypervisor cluster, = so that auto-failover and live migration works. The mail thing is that = we have a number of datacenters with a gigabit interconnect that is not= always 100% reliable. In the event of a failure we want all the virtua= l machines to fail over to the remaining datacenters, so we need all th= e data in each location. The other issue is that within each datacenter we can use link aggregat= ion to increase the bandwidth between hypervisors and the ceph cluster = but between the datacenters we only have the gigabit so it become essen= tial to have the hyperviors looking at the storage in the same datacent= er. Another consideration is that the virtual machines might get migrated b= etween datacenters without any failure, and the main problem I see with= Mark suggests is that in this mode the migrated VM would still be conn= ecting to the OSD's in the remote datacenter. Tbh Im fairly new to ceph and I know im asking for everything and the k= itchen sink! Any thoughts would be very helpful though. Thanks James ----- Original Message ----- =46rom: "Gregory Farnum" To: "Mark Kampe" Cc: "James Horner" , ceph-devel@vger.kern= el.org Sent: Tuesday, October 9, 2012 5:48:37 PM Subject: Re: Client Location On Tue, Oct 9, 2012 at 9:43 AM, Mark Kampe wro= te: > I'm not a real engineer, so please forgive me if I misunderstand, > but can't you create a separate rule for each data center (choosing > first a local copy, and then remote copies), which should ensure > that the primary is always local. Each data center would then > use a different pool, associated with the appropriate location- > sensitive rule. > > Does this approach get you the desired locality preference? This sounds right to me =E2=80=94 I think maybe there's a misunderstand= ing about how CRUSH works. What precisely are you after, James? -Greg -- 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