From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe Subject: Re: optmize librbd for iops Date: Tue, 13 Nov 2012 08:55:03 +0100 Message-ID: <50A1FCD7.7090303@profihost.ag> References: <50A0FE96.9030708@profihost.ag> <50A1FC14.3010007@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.profihost.ag ([85.158.179.208]:46633 "EHLO mail.profihost.ag" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752959Ab2KMHzD (ORCPT ); Tue, 13 Nov 2012 02:55:03 -0500 In-Reply-To: <50A1FC14.3010007@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Josh Durgin Cc: "ceph-devel@vger.kernel.org" Am 13.11.2012 08:51, schrieb Josh Durgin: > On 11/12/2012 05:50 AM, Stefan Priebe - Profihost AG wrote: >> Hello list, >> >> are there any plans to optimize librbd for iops? Right now i'm able to >> get 50.000 iop/s via iscsi and 100.000 iop/s using multipathing with >> iscsi. >> >> With librbd i'm stuck to around 18.000iops. As this scales with more >> hosts but not with more disks in a vm. It must be limited by rbd >> implementation in kvm / librbd. > > It'd be interesting to see which layers are most limiting in this > case - qemu/kvm, librados, or librbd. > > How does rados bench with 4k writes and then 4k reads with many > concurrent IOs do? Right now i'm using qemu-kvm with librbd and fio inside guest. How does the rados bench work? Stefan