From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Richardson Subject: Re: Ceph write performance Date: Fri, 20 Jul 2012 16:53:04 +0100 Message-ID: <50097EE0.4030603@ed.ac.uk> References: <500931CF.9040407@selectel.ru> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig67CAD26588A38EFD8B99A051" Return-path: Received: from treacle.ucs.ed.ac.uk ([129.215.16.102]:61090 "EHLO treacle.ucs.ed.ac.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753245Ab2GTPxW (ORCPT ); Fri, 20 Jul 2012 11:53:22 -0400 Received: from lmtp1.ucs.ed.ac.uk (lmtp1.ucs.ed.ac.uk [129.215.149.64]) by treacle.ucs.ed.ac.uk (8.13.8/8.13.4) with ESMTP id q6KFr83f026403 for ; Fri, 20 Jul 2012 16:53:14 +0100 (BST) Received: from [129.215.183.3] (pcw3047.see.ed.ac.uk [129.215.183.3]) (authenticated user=mrichar1 mech=PLAIN bits=0) by lmtp1.ucs.ed.ac.uk (8.13.8/8.13.7) with ESMTP id q6KFr4pn011281 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Fri, 20 Jul 2012 16:53:08 +0100 (BST) In-Reply-To: <500931CF.9040407@selectel.ru> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig67CAD26588A38EFD8B99A051 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 20/07/12 11:24, George Shuklin wrote: > Good day. >=20 > I've start to play with Ceph... And I found some kinda strange > performance issues. I'm not sure if this is due ceph limitation or my > bad setup. I'm seeing a similar problem which looks like a potential bug, which someone else seems to have already reported (http://www.spinics.net/lists/ceph-devel/msg07335.html and http://www.spinics.net/lists/ceph-devel/msg07691.html) The problem only seems to hit for me when I do random writes - can you try fio with sequential writes (rw=3Dwrite) and see if your problem also disappears? It might help confirm this as an issue. Thanks, Matthew --=20 The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. --------------enig67CAD26588A38EFD8B99A051 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iEYEARECAAYFAlAJfuAACgkQRWpi1WYCQdJYyQCeP4ru7VUY5vUmgtNMLvckQ5ef AnkAn3R6oqbE58M2Ew4HqzX2krV3M+53 =vu2+ -----END PGP SIGNATURE----- --------------enig67CAD26588A38EFD8B99A051--