From owner-freebsd-performance@FreeBSD.ORG Thu Apr 28 15:48:30 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 5A4AB16A4CE for ; Thu, 28 Apr 2005 15:48:30 +0000 (GMT) Received: from mh2.centtech.com (moat3.centtech.com [207.200.51.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id 42D1043D1D for ; Thu, 28 Apr 2005 15:48:29 +0000 (GMT) (envelope-from anderson@centtech.com) Received: from [10.177.171.220] (neutrino.centtech.com [10.177.171.220]) by mh2.centtech.com (8.13.1/8.13.1) with ESMTP id j3SFmSNB034879; Thu, 28 Apr 2005 10:48:28 -0500 (CDT) (envelope-from anderson@centtech.com) Message-ID: <42710594.2010308@centtech.com> Date: Thu, 28 Apr 2005 10:47:32 -0500 From: Eric Anderson User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.5) Gecko/20050325 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Steven Hartland References: <069901c54bfd$2967ba40$7f06000a@int.mediasurface.com> <4270F648.5030501@centtech.com> <06d301c54c02$98ab5ce0$7f06000a@int.mediasurface.com> In-Reply-To: <06d301c54c02$98ab5ce0$7f06000a@int.mediasurface.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: freebsd-performance@freebsd.org Subject: Re: Very low disk performance Highpoint 1820a 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: Thu, 28 Apr 2005 15:48:30 -0000 Steven Hartland wrote: > ----- Original Message ----- From: "Eric Anderson" > >>> Where do I start looking? > > >> First, understand that RAID 5 is dependant on fast hardware to >> performa the XOR operations. A single disk without any RAID can >> easily outperform a RAID array if the RAID array is on a 'slow' >> controller. The Highpoint controllers are not exactly high-end fast >> RAID controllers, so ~50MB/s isn't too bad for that I would say. Did >> you happen to try a vinum RAID5? How about a stripe? > > > The quoted benchmarks for this controller are ~500MB/s with 8 raptor > disks. Its a hardware RAID 5 with 8 SATA channels on 64Bit PCI-X > @ 133Mhz so under the current setup it should be achieving ~250MB/s > Im only getting 50MB/s which is just silly. > > It was also my inderstanding that the XOR is only done on write > not read. Correct - I misread the dd line. When you are doing the dd, what is your system busy doing? (top/ps info) >> You could make two RAID 5's with the controller, and then stripe those >> in vinum. You could also do a combo of two stripes in the controller, >> and a vinum mirror in FreeBSD - that would give you decent performance. > > > I could but it seems there is something more problematic a foot > here and would like to investigate the reason for the poor performance > not workaround it. What do you suspect? Some info from one of my arrays: # dd if=/dev/zero of=./testfile bs=64k count=10000 10000+0 records in 10000+0 records out 655360000 bytes transferred in 3.581413 secs (182989226 bytes/sec) (unmount / mount filesystem) # dd if=./testfile of=/dev/null bs=64k count=10000 10000+0 records in 10000+0 records out 655360000 bytes transferred in 6.747707 secs (97123362 bytes/sec) # dd if=/dev/da0s1d of=/dev/null bs=64k count=10000 10000+0 records in 10000+0 records out 655360000 bytes transferred in 11.252226 secs (58242699 bytes/sec) Seems like the reads should be faster than the writes.. Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology A lost ounce of gold may be found, a lost moment of time never. ------------------------------------------------------------------------