From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe - Profihost AG Subject: OSD Hardware questions Date: Wed, 27 Jun 2012 15:04:12 +0200 Message-ID: <4FEB04CC.4050008@profihost.ag> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.profihost.ag ([85.158.179.208]:59822 "EHLO mail.profihost.ag" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751720Ab2F0NEQ (ORCPT ); Wed, 27 Jun 2012 09:04:16 -0400 Sender: ceph-devel-owner@vger.kernel.org List-ID: To: "ceph-devel@vger.kernel.org" Hello list, i'm still thinking about optimal OSD hardware and while reading through the mailinglist and wiki had some questions. I want to use SSD so my idea was to use a fast single socket cpu with 8-10 SSD disks per OSD. I got the following recommandations through the mailinglist: "Dual socket servers will be overkill given the setup you're describing. Our WAG rule of thumb is 1GHz of modern CPU per OSD daemon. You might consider it if you decided you wanted to do an OSD per disk instead (that's a more common configuration, but it requires more CPU and RAM per disk and we don't know yet which is the better choice)." but in my tests i see a CPU usage of 160% + 15% kworker per OSD Daemon on a 3,6ghz intel xeon CPU. That's far away of 1GHz per OSD. That's around 6,3Ghz per OSD. Is anything wrong here? When i want to use 8-10 SSD Disks i need around 20 cores with 3,6Ghz. But there is no single socket with 20 cores with 3,6Ghz. Or should i consider using a Raid 5 or 6? Anything wrong? Stefan