From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Dawson Subject: Guidelines for Calculating IOPS? Date: Fri, 19 Oct 2012 10:47:46 -0400 Message-ID: <50816812.2040008@gammacode.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from 23-25-46-103-static.hfc.comcastbusiness.net ([23.25.46.103]:46399 "EHLO mail1.gammacode.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932959Ab2JSO55 (ORCPT ); Fri, 19 Oct 2012 10:57:57 -0400 Received: from localhost (mail1.gammacode.com [127.0.0.1]) by mail1.gammacode.com (iRedMail) with ESMTP id F28E23D802E for ; Fri, 19 Oct 2012 10:46:35 -0400 (EDT) Received: from mail1.gammacode.com ([127.0.0.1]) by localhost (mail1.gammacode.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 9Ih97fqfHaMp for ; Fri, 19 Oct 2012 10:46:35 -0400 (EDT) Received: from [10.10.1.203] (unknown [10.10.1.203]) by mail1.gammacode.com (iRedMail) with ESMTPSA id 4E62E3D802D for ; Fri, 19 Oct 2012 10:46:35 -0400 (EDT) Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel@vger.kernel.org All, I am investigating the use of Ceph for a video surveillance project with the following minimum block storage requirements: 385 Mbps of constant write bandwidth 100TB storage requirement 5250 IOPS (size of ~8 KB) I believe 2 replicas would be acceptable. We intend to use large capacity (2 or 3TB) SATA 7200rpm 3.5" drives, if the IOPS work out properly. Is there a method / formula to estimate IOPS for RDB? Specifically I would like to understand: - How does replica count affect read/write IOPS? - I'm trying to understand best practice for when to optimize server count, drives per server, and drive capacity as it relates to IOPS. Is there a point of diminishing I/O performance using server chassis with lots of drive slots, like the 36-drive Supermicro SC847a? Thanks, Mike