From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Mick Subject: Re: ceph and efficient access of distributed resources Date: Mon, 15 Apr 2013 15:25:25 -0700 Message-ID: <516C7E55.1050801@inktank.com> References: <51683184.9010301@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pb0-f43.google.com ([209.85.160.43]:49024 "EHLO mail-pb0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753846Ab3DOWZ3 (ORCPT ); Mon, 15 Apr 2013 18:25:29 -0400 Received: by mail-pb0-f43.google.com with SMTP id md4so2779297pbc.16 for ; Mon, 15 Apr 2013 15:25:28 -0700 (PDT) In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Gandalf Corvotempesta Cc: Mark Nelson , Matthias Urlichs , "ceph-devel@vger.kernel.org" On 04/15/2013 01:06 PM, Gandalf Corvotempesta wrote: > 2013/4/12 Mark Nelson > >> Currently reads always come from the primary OSD in the placement group >> rather than a secondary even if the secondary is closer to the client. >> > > In this way, only one OSD will be involved in reading an object, this will > result in a bottleneck if multiple clients needs to access to the same file. > > For example, a 3KB CSS file served by a webserver to 400 users, will be > read just from one OSD. 400 users directed to 1 OSD while (in case of > replica 3) other 2 OSDs are available? Yes. Consistency across the cluster is dependent on this scheme, currently.