From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Durgin Subject: Re: how to debug slow rbd block device Date: Wed, 23 May 2012 01:29:51 -0700 Message-ID: <4FBC9FFF.6090605@inktank.com> References: <4FBB8A5B.9010500@profihost.ag> <4FBBEBC8.1000205@profihost.ag> <1C70F3FB753C4AEC97247E04FAE3C733@inktank.com> <4FBBF74C.9020608@profihost.ag> <45F1742481D84E7A90951816DB23609F@inktank.com> <4FBBFE7B.4060406@profihost.ag> <65E9589544C4489F93761035433ADC01@inktank.com> <4FBC811F.5060004@profihost.ag> <4FBC83F3.7070400@inktank.com> <4FBC8B41.1020300@profihost.ag> <4FBC8F8F.6060004@inktank.com> <4FBC9DDB.5090507@profihost.ag> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-pb0-f46.google.com ([209.85.160.46]:39599 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757570Ab2EWI3y (ORCPT ); Wed, 23 May 2012 04:29:54 -0400 Received: by pbbrp8 with SMTP id rp8so9564451pbb.19 for ; Wed, 23 May 2012 01:29:53 -0700 (PDT) In-Reply-To: <4FBC9DDB.5090507@profihost.ag> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Stefan Priebe - Profihost AG Cc: Greg Farnum , ceph-devel@vger.kernel.org On 05/23/2012 01:20 AM, Stefan Priebe - Profihost AG wrote: > Am 23.05.2012 09:19, schrieb Josh Durgin: >> On 05/23/2012 12:01 AM, Stefan Priebe - Profihost AG wrote: >>> Am 23.05.2012 08:30, schrieb Josh Durgin: >>>> On 05/22/2012 11:18 PM, Stefan Priebe - Profihost AG wrote: >>>>> Hi, >>>>> >>>>>>> So try enabling RBD writeback caching =E2=80=94 see http://marc= =2Einfo >>>>>>> /?l=3Dceph-devel&m=3D133758599712768&w=3D2 >>>>>>> will test tomorrow. Thanks. >>>>> Can we path this to the qemu-drive option? >>>> >>>> Yup, see >>>> http://article.gmane.org/gmane.comp.file-systems.ceph.devel/6400 >>> I'm sorry, i still don't get it where to pass rbd_cache_max_dirty, = =2E.. >>> can i add it just to the ceph.conf? Even with qemu 1.0? >> >> You can use any of the rbd-specific options (like rbd_cache_max_dirt= y) >> with qemu>=3D 0.15. >> >> You can set them in a global ceph.conf file, or specify them on the = qemu >> command line like: >> >> qemu -m 512 -drive >> file=3Drbd:pool/image:rbd_cache_max_dirty=3D0:rbd_cache=3Dtrue,forma= t=3Draw,if=3Dvirtio > > So this is enough for testing on kvm host? > > /etc/ceph/ceph.conf > > [global] > auth supported =3D cephx > keyring =3D /etc/ceph/$name.keyring > rbd_cache =3D true > rbd_cache_size =3D 32M This should be a number in bytes - M/G/k/etc aren't parsed. Assuming yo= u=20 have the monitors listed below, this is fine. If you're not using the=20 admin user, you'll need to add :id=3Dname to the -drive string - it can= 't=20 be set in the config file. > rbd_cache_max_age =3D 2.0 > > ... > > Stefan -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html