From mboxrd@z Thu Jan 1 00:00:00 1970 From: Miles Fidelman Subject: possibly silly question (raid failover) Date: Mon, 31 Oct 2011 20:38:16 -0400 Message-ID: <4EAF3F78.5060900@meetinghouse.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: "linux-raid@vger.kernel.org" List-Id: linux-raid.ids Hi Folks, I've been exploring various ways to build a "poor man's high availability cluster." Currently I'm running two nodes, using raid on each box, running DRBD across the boxes, and running Xen virtual machines on top of that. I now have two brand new servers - for a total of four nodes - each with four large drives, and four gigE ports. Between the configuration of the systems, and rack space limitations, I'm trying to use each server for both storage and processing - and been looking at various options for building a cluster file system across all 16 drives, that supports VM migration/failover across all for nodes, and that's resistant to both single-drive failures, and to losing an entire server (and it's 4 drives), and maybe even losing two servers (8 drives). The approach that looks most interesting is Sheepdog - but it's both tied to KVM rather than Xen, and a bit immature. But it lead me to wonder if something like this might make sense: - mount each drive using AoE - run md RAID 10 across all 16 drives one one node - mount the resulting md device using AoE - if the node running the md device fails, use pacemaker/crm to auto-start an md device on another node, re-assemble and republish the array - resulting in a 16-drive raid10 array that's accessible from all nodes Or is this just silly and/or wrongheaded? Miles Fidelman -- In theory, there is no difference between theory and practice. In practice, there is. .... Yogi Berra