From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe Subject: Re: poor OSD performance using kernel 3.4 Date: Thu, 24 May 2012 21:05:06 +0200 Message-ID: <4FBE8662.1070801@profihost.ag> References: <4FBE415E.8030702@profihost.ag> <4FBE7ABC.5020502@profihost.ag> <4FBE838D.4000303@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.profihost.ag ([85.158.179.208]:44655 "EHLO mail.profihost.ag" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751961Ab2EXTFH (ORCPT ); Thu, 24 May 2012 15:05:07 -0400 In-Reply-To: <4FBE838D.4000303@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Mark Nelson Cc: "ceph-devel@vger.kernel.org" Am 24.05.2012 20:53, schrieb Mark Nelson: > Hi Stefan, > > Thanks for the info! I've been testing on 3.4 for the last couple of > days but haven't run into that problem here. It looks like your journal > has writes going to it quickly and then things stall as it tries to > write out to your data disk. That's a good point. Right now while testing i'm using a tmpfs ramdisk for the journal and have set journal dio = false in ceph.conf? Might this be the difference / problem? 3.2.18 works fine too. > I wonder if any of the data actually makes > it to the disk... Can you run iostat or collectl or something and see > what kind of write throughput you get to the OSD data disks? none... so it seems get's never transferred from journal to disk. Stefan