From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe Subject: Re: how to debug slow rbd block device Date: Tue, 22 May 2012 22:30:04 +0200 Message-ID: <4FBBF74C.9020608@profihost.ag> References: <4FBB8A5B.9010500@profihost.ag> <4FBBEBC8.1000205@profihost.ag> <1C70F3FB753C4AEC97247E04FAE3C733@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]:43789 "EHLO mail.profihost.ag" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760372Ab2EVUaH (ORCPT ); Tue, 22 May 2012 16:30:07 -0400 In-Reply-To: <1C70F3FB753C4AEC97247E04FAE3C733@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Greg Farnum Cc: ceph-devel@vger.kernel.org Am 22.05.2012 21:52, schrieb Greg Farnum: > On Tuesday, May 22, 2012 at 12:40 PM, Stefan Priebe wrote: > Huh. That's less than I would expect. Especially since it ought to be going through the page cache. > What version of RBD is KVM using here? v0.47.1 > Can you (from the KVM host) run > "rados -p data bench seq 60 -t 1" > "rados -p data bench seq 60 -t 16" > and paste the final output from both? OK here it is first with write then with seq read. # rados -p data bench 60 write -t 1 # rados -p data bench 60 write -t 16 # rados -p data bench 60 seq -t 1 # rados -p data bench 60 seq -t 16 Output is here: http://pastebin.com/iFy8GS7i Thanks! Stefan