Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1U7wMj-0001Pt-Pk for pgsql-performance@arkaria.postgresql.org; Tue, 19 Feb 2013 23:12:50 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.72) (envelope-from ) id 1U7wMj-0007sv-15 for pgsql-performance@arkaria.postgresql.org; Tue, 19 Feb 2013 23:12:49 +0000 Received: from makus.postgresql.org ([2001:4800:7903:4::125]) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1U7wMh-0007sh-UG for pgsql-performance@postgresql.org; Tue, 19 Feb 2013 23:12:48 +0000 Received: from [2404:130:0:10::40:2] (helo=mail.catalyst.net.nz) by makus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1U7wMf-0001cm-1g for pgsql-performance@postgresql.org; Tue, 19 Feb 2013 23:12:45 +0000 Received: from localhost (localhost [127.0.0.1]) by mail.catalyst.net.nz (Postfix) with ESMTP id 9687932EEF; Wed, 20 Feb 2013 12:12:36 +1300 (NZDT) X-Virus-Scanned: Debian amavisd-new at catalyst.net.nz Received: from mail.catalyst.net.nz ([127.0.0.1]) by localhost (bertrand.catalyst.net.nz [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id K0gimUFMyTQS; Wed, 20 Feb 2013 12:12:35 +1300 (NZDT) Received: from [IPv6:2404:130:0:1000:3943:c1bb:fa0e:6850] (unknown [IPv6:2404:130:0:1000:3943:c1bb:fa0e:6850]) (Authenticated sender: mark.kirkwood) by mail.catalyst.net.nz (Postfix) with ESMTPSA id D9D163281C; Wed, 20 Feb 2013 12:12:35 +1300 (NZDT) Message-ID: <51240802.2090006@catalyst.net.nz> Date: Wed, 20 Feb 2013 12:17:22 +1300 From: Mark Kirkwood User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: Josh Berkus CC: postgres performance list Subject: Re: High CPU usage / load average after upgrading to Ubuntu 12.04 References: <60B572D9298D944580F7D51195DD30804357FA4ABF@VMBX125.ihostexchange.net> <60B572D9298D944580F7D51195DD30804357FA4B60@VMBX125.ihostexchange.net> <60B572D9298D944580F7D51195DD30804357FA4C11@VMBX125.ihostexchange.net> <511BE879.8080706@agliodbs.com> <511C2F10.3080409@agliodbs.com> <60B572D9298D944580F7D51195DD30804357FA4DE2@VMBX125.ihostexchange.net> <511D2F11.6040706@agliodbs.com> <60B572D9298D944580F7D51195DD308043580CAA0B@VMBX125.ihostexchange.net> <511D79FE.7060705@agliodbs.com> <60B572D9298D944580F7D51195DD308043580CAA87@VMBX125.ihostexchange.net> <511E7DC0.4090506@agliodbs.com> <5122C507.7060303@agliodbs.com> <5122C9D9.9040909@agliodb s.com> <5122FF50.8030903@catalyst.net.nz> <5123BB94.7030603@agliodbs .com> In-Reply-To: <5123BB94.7030603@agliodbs.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Host-Lookup-Failed: Reverse DNS lookup failed for 2404:130:0:10::40:2 (failed) X-Pg-Spam-Score: -1.1 (-) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org On 20/02/13 06:51, Josh Berkus wrote: > On 02/18/2013 08:28 PM, Mark Kirkwood wrote: >> Might be worth looking at your vm.dirty_ratio, vm.dirty_background_ratio >> and friends settings. We managed to choke up a system with 16x SSD by >> leaving them at their defaults... > Yeah? Any settings you'd recommend specifically? What did you use on > the SSD system? > We set: vm.dirty_background_ratio = 0 vm.dirty_background_bytes = 1073741824 vm.dirty_ratio = 0 vm.dirty_bytes = 2147483648 i.e 1G for dirty_background and 2G for dirty. We didn't spend much time afterwards fiddling with the size much. I'm guessing the we could have made it bigger - however the SSD were happier to be constantly writing a few G than being handed (say) 50G of buffers to write at once . The system has 512G of ram and 32 cores (no hyperthreading). regards Mark -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance