From owner-freebsd-performance@FreeBSD.ORG Mon May 2 22:23:14 2005 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id EA8A116A4CE; Mon, 2 May 2005 22:23:13 +0000 (GMT) Received: from multiplay.co.uk (www1.multiplay.co.uk [212.42.16.7]) by mx1.FreeBSD.org (Postfix) with ESMTP id DCE0143D7F; Mon, 2 May 2005 22:23:12 +0000 (GMT) (envelope-from killing@multiplay.co.uk) Received: from vader ([212.135.219.179]) by multiplay.co.uk (multiplay.co.uk [212.42.16.7]) (MDaemon.PRO.v8.0.1.R) with ESMTP id md50001376600.msg; Mon, 02 May 2005 23:19:28 +0100 Message-ID: <001f01c54f65$80231080$b3db87d4@multiplay.co.uk> From: "Steven Hartland" To: "Steven Hartland" , "Poul-Henning Kamp" References: <19879.1115061648@critter.freebsd.dk> <00fe01c54f61$df220d60$b3db87d4@multiplay.co.uk> Date: Mon, 2 May 2005 23:22:57 +0100 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2527 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2527 X-Spam-Processed: multiplay.co.uk, Mon, 02 May 2005 23:19:28 +0100 (not processed: message from valid local sender) X-MDRemoteIP: 212.135.219.179 X-Return-Path: killing@multiplay.co.uk X-MDAV-Processed: multiplay.co.uk, Mon, 02 May 2005 23:19:30 +0100 cc: Eric Anderson cc: freebsd-performance@freebsd.org cc: Robert Watson Subject: Re: Very low disk performance on 5.x X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 May 2005 22:23:14 -0000 ----- Original Message ----- > > Raw read: > /usr/bin/time -h dd of=/dev/null if=/dev/da0 bs=64k count=100000 > 100000+0 records in > 100000+0 records out > 6553600000 bytes transferred in 32.028544 secs (204617482 bytes/sec) > 32.02s real 0.02s user 2.73s sys Out of curiosity just recreated the array with a 64K stripe ( the default ) /usr/bin/time -h dd of=/dev/null if=/dev/da0 bs=64k count=100000 100000+0 records in 100000+0 records out 6553600000 bytes transferred in 61.246992 secs (107002806 bytes/sec) 1m1.24s real 0.06s user 2.83s sys /usr/bin/time -h dd of=/dev/null if=/dev/da0 bs=128k count=50000 50000+0 records in 50000+0 records out 6553600000 bytes transferred in 59.532993 secs (110083496 bytes/sec) 59.53s real 0.00s user 1.86s sys And a 32k stripe: /usr/bin/time -h dd of=/dev/null if=/dev/da0 bs=64k count=100000 100000+0 records in 100000+0 records out 6553600000 bytes transferred in 41.947912 secs (156231853 bytes/sec) 41.94s real 0.04s user 2.80s sys So here the smaller the stripe the higher the transfer rate. Some RAID0 results: 64k stripe: /usr/bin/time -h dd of=/dev/null if=/dev/da0 bs=64k count=100000 100000+0 records in 100000+0 records out 6553600000 bytes transferred in 59.255960 secs (110598158 bytes/sec) 59.25s real 0.04s user 2.52s sys 32k stripe: /usr/bin/time -h dd of=/dev/null if=/dev/da0 bs=64k count=100000 100000+0 records in 100000+0 records out 6553600000 bytes transferred in 39.402059 secs (166326333 bytes/sec) 39.40s real 0.00s user 2.96s sys 16k stripe: /usr/bin/time -h dd of=/dev/null if=/dev/da0 bs=64k count=100000 100000+0 records in 100000+0 records out 6553600000 bytes transferred in 31.954544 secs (205091332 bytes/sec) 31.95s real 0.04s user 2.73s sys Conclusion from this is that at 16K stripe size RAID5 is identical read performance of RAID0 which is what I would expect. Steve ================================================ This e.mail is private and confidential between Multiplay (UK) Ltd. and the person or entity to whom it is addressed. In the event of misdirection, the recipient is prohibited from using, copying, printing or otherwise disseminating it or any information contained in it. In the event of misdirection, illegible or incomplete transmission please telephone (023) 8024 3137 or return the E.mail to postmaster@multiplay.co.uk.