From owner-freebsd-current@FreeBSD.ORG Sun May 8 21:22:57 2005 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 348E016A4E6; Sun, 8 May 2005 21:22:57 +0000 (GMT) Received: from freebee.digiware.nl (dsl439.iae.nl [212.61.63.187]) by mx1.FreeBSD.org (Postfix) with ESMTP id 187A843D9F; Sun, 8 May 2005 21:22:56 +0000 (GMT) (envelope-from wjw@withagen.nl) Received: from [212.61.27.71] (dual.digiware.nl [212.61.27.71]) by freebee.digiware.nl (8.13.1/8.13.1) with ESMTP id j48LMhJ3083834; Sun, 8 May 2005 23:22:45 +0200 (CEST) (envelope-from wjw@withagen.nl) Message-ID: <427E8324.8010905@withagen.nl> Date: Sun, 08 May 2005 23:22:44 +0200 From: Willem Jan Withagen User-Agent: Mozilla Thunderbird 0.9 (Windows/20041103) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Steven Hartland References: <069901c54bfd$2967ba40$7f06000a@int.mediasurface.com> <427D5AA0.1080609@withagen.nl> <002b01c553be$93a5b790$b3db87d4@multiplay.co.uk> <427E05D2.2060706@digiware.nl> <002b01c553db$5e167340$b3db87d4@multiplay.co.uk> In-Reply-To: <002b01c553db$5e167340$b3db87d4@multiplay.co.uk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit cc: freebsd-hackers@freebsd.org cc: willem jan withagen cc: freebsd-current@freebsd.org Subject: Re: Very low disk performance Highpoint 1820a X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 08 May 2005 21:22:57 -0000 Steven Hartland wrote: >> Still I would argue that if you do not use a write size larger than >> what you have as real memory, that buffering in real memory is going >> to play a role.... > > > I think you miss read all the details here Willem. Sorry about that, if that is the case. > Original values: > Write: 150Mb/s > Read: 50Mb/s > Current value after tweeking, RAID stripe size, vfs.read_max and > MAXPHYS ( needs more testing now due to scotts warning ) > Write: 150Mb/s > Read: 200Mb/s > > Note: The test size was upped to 10Gb to avoid caching issues. That would certainly negate my assumption 10G is enough to regularly flush the buffer. >> Other than that I find 50Mb/s is IMHO reasonable high value for a >> RAID5 in writting. But it would require substantial more organised >> testing. DD is nothing more than a very crude indication of what to >> expect in real life. > > > dd was uses as it is a good quick indication of baseline sequential file > access > speed and as such highlighted a serious issue with the original > performance. That is well phrased English for what I was trying to say. I'm glad to see that it worked for you. And I'm certainly impressed by the numbers... This is on a 4 disk RAID5 with one hot spare??? --WjW