From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Mitchell Subject: Re: Understanding Ceph Date: Sat, 19 Jan 2013 13:08:22 -0500 Message-ID: <50FAE116.2010504@gmail.com> References: <50FAC92C.8030709@bmrb.wisc.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-vc0-f176.google.com ([209.85.220.176]:49919 "EHLO mail-vc0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752240Ab3ASSI1 (ORCPT ); Sat, 19 Jan 2013 13:08:27 -0500 Received: by mail-vc0-f176.google.com with SMTP id fy27so204265vcb.7 for ; Sat, 19 Jan 2013 10:08:27 -0800 (PST) In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Sage Weil Cc: Peter Smith , Dimitri Maziuk , ceph-devel@vger.kernel.org Sage Weil wrote: > On Sun, 20 Jan 2013, Peter Smith wrote: >> Thanks for the reply, Sage and everyone. >> >> Sage, so I can expect Ceph-rbd works well on Centos 6.3 if I only use >> it as the Cinder volume backend because the librbd in QEMU doesn't >> make use of kernel client, right? > > Then the dependency is on the qemu version. I don't remember that off the > top of my head, or know what version rhel6 ships. Most people deploying > openstack and rbd are using a more modern distro (like ubuntu 12.04). This discussion has made me curious: I'm using Ganeti to manage VMs, which manages the storage using the kernel client and passes in the dev device to qemu. Can you comment on any known performance differences between the two methods -- native qemu+librbd creating a block device vs. the kernel client creating a block device? Thanks, Jeff