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 21:40:56 +0200 Message-ID: <4FBBEBC8.1000205@profihost.ag> References: <4FBB8A5B.9010500@profihost.ag> 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]:45841 "EHLO mail.profihost.ag" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753253Ab2EVTk6 (ORCPT ); Tue, 22 May 2012 15:40:58 -0400 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Greg Farnum Cc: ceph-devel@vger.kernel.org Am 22.05.2012 21:35, schrieb Greg Farnum: > What does your test look like? With multiple large IOs in flight we can regularly fill up a 1GbE link on our test clusters. With smaller or fewer IOs in flight performance degrades accordingly. iperf shows 950Mbit/s so this is OK (from KVM host to OSDs) sorry: dd if=/dev/zero of=test bs=4M count=1000; dd if=test of=/dev/null bs=4M count=1000; 1000+0 records in 1000+0 records out 4194304000 bytes (4,2 GB) copied, 99,7352 s, 42,1 MB/s 1000+0 records in 1000+0 records out 4194304000 bytes (4,2 GB) copied, 47,4493 s, 88,4 MB/s Greets Stefan > On Tuesday, May 22, 2012 at 5:45 AM, Stefan Priebe - Profihost AG wrote: > >> Hi list, >> >> my ceph block testcluster is now running fine. >> >> Setup: >> 4x ceph servers >> - 3x mon with /mon on local os SATA disk >> - 4x OSD with /journal on tmpfs and /srv on intel ssd >> >> all of them use 2x 1Gbit/s lacp trunk. >> >> 1x KVM Host system (2x 1Gbit/s lacp trunk) >> >> With one KVM i do not get more than 40MB/s and my network link is just >> at 40% of 1Gbit/s. >> >> Is this expected? If not where can i start searching / debugging? >> >> Thanks, >> Stefan >> -- >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> the body of a message to majordomo@vger.kernel.org (mailto:majordomo@vger.kernel.org) >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > >