From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Richardson Subject: Re: Ceph RBD performance - random writes Date: Thu, 09 Aug 2012 15:48:50 +0100 Message-ID: <5023CDD2.6040307@ed.ac.uk> References: <5021F6D1.7000004@catalyst.net.nz> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig804B3C354ABDCFB3B2491CB0" Return-path: Received: from nougat.ucs.ed.ac.uk ([129.215.13.205]:38523 "EHLO nougat.ucs.ed.ac.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751293Ab2HIPYL (ORCPT ); Thu, 9 Aug 2012 11:24:11 -0400 Received: from lmtp1.ucs.ed.ac.uk (lmtp1.ucs.ed.ac.uk [129.215.149.64]) by nougat.ucs.ed.ac.uk (8.13.8/8.13.4) with ESMTP id q79EmoXT024903 for ; Thu, 9 Aug 2012 15:48:52 +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 q79Emo8B028301 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Thu, 9 Aug 2012 15:48:50 +0100 (BST) In-Reply-To: <5021F6D1.7000004@catalyst.net.nz> 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) --------------enig804B3C354ABDCFB3B2491CB0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 08/08/12 06:19, Mark Kirkwood wrote: > I've been looking at using Ceph RBD as a block store for database use. > As part of this I'm looking a how (particularly random) IO of smallish > (4K, 8K) block sizes performs. It may or may not be related, but have a look at the message thread here:= http://www.mail-archive.com/ceph-devel@vger.kernel.org/msg07678.html It looks like there might be a specific bug relating to random writes. Matthew --=20 The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. --------------enig804B3C354ABDCFB3B2491CB0 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) iEYEARECAAYFAlAjzdIACgkQRWpi1WYCQdKpkwCfXlskKRT0wqZw1ClBoC5m2wZ2 wm0AoJm6/pCsJ89OKNVm2MLDWVTdyUOL =h8Z4 -----END PGP SIGNATURE----- --------------enig804B3C354ABDCFB3B2491CB0--