From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe Subject: Re: speedup ceph / scaling / find the bottleneck Date: Sun, 01 Jul 2012 23:27:30 +0200 Message-ID: <4FF0C0C2.2010407@profihost.ag> References: <4FED8792.1090905@profihost.ag> <4FED964D.3080201@inktank.com> <4FEDA777.1060309@profihost.ag> <4FEE1B91.8080404@profihost.ag> <4FF0BAB8.3070503@profihost.ag> <4FF0BD84.1050607@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.profihost.ag ([85.158.179.208]:53899 "EHLO mail.profihost.ag" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751882Ab2GAV12 (ORCPT ); Sun, 1 Jul 2012 17:27:28 -0400 In-Reply-To: <4FF0BD84.1050607@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Mark Nelson Cc: Sage Weil , "ceph-devel@vger.kernel.org" Am 01.07.2012 23:13, schrieb Mark Nelson: > On 7/1/12 4:01 PM, Stefan Priebe wrote: >> Hello list, >> Hello sage, >> >> i've made some further tests. >> >> Sequential 4k writes over 200GB: 300% CPU usage of kvm process 34712 iops >> >> Random 4k writes over 200GB: 170% CPU usage of kvm process 5500 iops >> >> When i make random 4k writes over 100MB: 450% CPU usage of kvm process >> and !! 25059 iops !! >> > When you say 100MB vs 200GB, do you mean the total amount of data that > is written for the test? Yes/No, it is the max amount of data written but for random I/O it is also the range like random block device position between 0 and X where to write the 4K block. > Also, are these starting out on a fresh > filesystem? Yes, 5 Min old in this case ;-) Stefan