Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1Zk9Tl-0005vw-4D for pgsql-performance@arkaria.postgresql.org; Thu, 08 Oct 2015 11:35:21 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84) (envelope-from ) id 1Zk9Tk-0001Lb-IG for pgsql-performance@arkaria.postgresql.org; Thu, 08 Oct 2015 11:35:20 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84) (envelope-from ) id 1Zk9S7-0007se-8i for pgsql-performance@postgresql.org; Thu, 08 Oct 2015 11:33:39 +0000 Received: from mail.tivas.info ([85.234.217.139]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84) (envelope-from ) id 1Zk9Rv-00041C-76 for pgsql-performance@postgresql.org; Thu, 08 Oct 2015 11:33:38 +0000 Received: from localhost.localdomain ([192.168.3.104]) by mail.tivas.info (8.14.7/8.14.7) with ESMTP id t98BXMF7097778; Thu, 8 Oct 2015 13:33:22 +0200 (CEST) (envelope-from bram@diomedia.be) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=diomedia.be; s=mail; t=1444304002; bh=FZCmVTB0ZcGWEf2tGPiVg28lZpm23s9gsZLrhSia7OU=; h=Date:From:To:CC:Subject:References:In-Reply-To; b=TPgGc9IgEogZwQQozJtE69sOFS1GOci+JI1NxFhjzwnF93jcF2CZmcIP2PmufwoxO 0WM988v//z0UKyrbwjjnU7CihLt1B5eIC0NFk5SEYIROY5cjH/FKA+l7FoTXYEKFTa LJXVeo6MYiqluNhkQfpYMYBW9pjQXizZHW44lkvY= Message-ID: <56165482.7030109@diomedia.be> Date: Thu, 08 Oct 2015 13:33:22 +0200 From: Bram Van Steenlandt User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: "Graeme B. Bell" CC: "pgsql-performance@postgresql.org list" Subject: Re: large object write performance References: <561634BD.2000309@diomedia.be> <8809EA0A-C7DE-4CC3-B2E4-9F0062A91B93@skogoglandskap.no> <56164EE1.5020208@diomedia.be> <465F0A34-AE24-457A-8B3E-60440862D7EF@skogoglandskap.no> In-Reply-To: <465F0A34-AE24-457A-8B3E-60440862D7EF@skogoglandskap.no> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-MessageSniffer-RulebaseUTC: 20150811174000 X-MessageSniffer-Identifier: <56165482.7030109@diomedia.be> X-GBUdb-Analysis: 0, 192.168.3.104, Ugly c=0.38014 p=-0.55 Source Normal X-MessageSniffer-Scan-Result: 0 X-MessageSniffer-Rules: 0-0-0-3731-c X-Pg-Spam-Score: -2.0 (--) 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 Op 08-10-15 om 13:21 schreef Graeme B. Bell: >>> First the database was on a partition where compression was enabled, I changed it to an uncompressed one to see if it makes a difference thinking maybe the cpu couldn't handle the load. >> It made little difference in my case. >> >> My regular gmirror partition seems faster: >> dd bs=8k count=25600 if=/dev/zero of=./test >> 25600+0 records in >> 25600+0 records out >> 209715200 bytes transferred in 1.513112 secs (138598612 bytes/sec) >> >> the zfs compressed partition also goes faster: >> dd bs=8k count=25600 if=/dev/zero of=./test >> 25600+0 records in >> 25600+0 records out >> 209715200 bytes transferred in 0.979065 secs (214199479 bytes/sec) >> but this one didn't really go that fast in my test (maybe 10%) > > Please can you run iozone and look for low random write performance with small blocks? (4k) > http://www.slashroot.in/linux-file-system-read-write-performance-test Like this ? gmirror (iozone -s 4 -a /dev/mirror/gm0s1e) = 806376 (faster drives) zfs uncompressed (iozone -s 4 -a /datapool/data) = 650136 zfs compressed (iozone -s 4 -a /datapool/data) = 676345 > Also please can you CC to the list with your replies to my on-list emails? > > Graeme Bell > > -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance