Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1XypNq-0003oH-I2 for pgsql-performance@arkaria.postgresql.org; Wed, 10 Dec 2014 22:05:22 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1XypNp-00052D-N5 for pgsql-performance@arkaria.postgresql.org; Wed, 10 Dec 2014 22:05:21 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1XypNo-000525-Q7 for pgsql-performance@postgresql.org; Wed, 10 Dec 2014 22:05:20 +0000 Received: from mail.catalyst.net.nz ([2404:130:0:10::40:0]) by makus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1XypNl-0002LB-Dq for pgsql-performance@postgresql.org; Wed, 10 Dec 2014 22:05:19 +0000 Received: from localhost (localhost [127.0.0.1]) by mail.catalyst.net.nz (Postfix) with ESMTP id 3255431D82; Thu, 11 Dec 2014 11:05:16 +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 CtwJiZVaXXQb; Thu, 11 Dec 2014 11:05:15 +1300 (NZDT) Received: from [IPv6:2404:130:0:1000:d04f:401b:daa9:e9d] (unknown [IPv6:2404:130:0:1000:d04f:401b:daa9:e9d]) (Authenticated sender: mark.kirkwood) by mail.catalyst.net.nz (Postfix) with ESMTPSA id DF0F131D31; Thu, 11 Dec 2014 11:05:14 +1300 (NZDT) Message-ID: <5488C39A.8080904@catalyst.net.nz> Date: Thu, 11 Dec 2014 11:05:14 +1300 From: Mark Kirkwood User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: =?UTF-8?B?U3RyYWhpbmphIEt1c3R1ZGnEhw==?= CC: "pgsql-performance@postgresql.org" Subject: Re: 8xIntel S3500 SSD in RAID10 on Dell H710p References: <5487C422.2000306@catalyst.net.nz> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Pg-Spam-Score: -1.9 (-) 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 10/12/14 21:30, Strahinja Kustudić wrote: > On Wed, Dec 10, 2014 at 4:55 AM, Mark Kirkwood < > mark.kirkwood@catalyst.net.nz> wrote: > >> That is interesting: I've done some testing on this type of card with 16 >> (slightly faster Hitachi) SSD attached. Setting WT and NORA should enable >> the so-called 'fastpath' mode for the card [1]. We saw performance improve >> markedly (300MB/s random write go to 1300MB/s). >> >> This *might* be related to the fact that 16 SSD can put out more IOPS than >> the card can actually handle - whereas your 8 S3500 is probably the perfect >> number (e.g 8*11000 = 88000 which the card can handle ok). >> >> >> [1] If you make the change while there are no outstanding background >> operations (array rebuild etc) in progress (see >> http://www.flagshiptech.com/eBay/Dell/poweredgeh310h710h810UsersGuide.pdf >> ). > > > I read that guide too, which is the reason why I tried with WT/NORA, but > the document also states: "NOTE: RAID 10, RAID 50, and RAID 60 virtual > disks cannot use FastPath." Which is a little odd, since usually if you > want performance with reliability, you go RAID10. > > Do you have any suggestions what I could try to tweak to get more > performance? > We are using these configured as *individual* drives on RAID0 that are then md raided in a (software) RAID 10 array. Maybe try that out (as fastpath only cares about the HW RAID setup). Interestingly we were also seeing better performance on a fully HW RAID 10 array with WT/NORA...so (I guess) our Hitachi SSD probably have lower latency than the S3500 does. Cheers Mark -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance