From owner-freebsd-performance@FreeBSD.ORG Wed Jun 18 13:44:28 2003 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 5E35537B401 for ; Wed, 18 Jun 2003 13:44:28 -0700 (PDT) Received: from otter3.centtech.com (moat3.centtech.com [207.200.51.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id 939D043F93 for ; Wed, 18 Jun 2003 13:44:25 -0700 (PDT) (envelope-from anderson@centtech.com) Received: from centtech.com (electron.centtech.com [204.177.173.173]) by otter3.centtech.com (8.12.3/8.12.3) with ESMTP id h5IKiO56037104; Wed, 18 Jun 2003 15:44:25 -0500 (CDT) (envelope-from anderson@centtech.com) Message-ID: <3EF0CF1E.9020901@centtech.com> Date: Wed, 18 Jun 2003 15:44:14 -0500 From: Eric Anderson User-Agent: Mozilla/5.0 (X11; U; Linux i386; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 X-Accept-Language: en-us, en MIME-Version: 1.0 To: "Jin Guojun [DSD]" References: <20030614190033.7F0DE37B407@hub.freebsd.org> <20030615091254.M85497@bluhayz.org> <3EF0B507.2B1B6FDF@lbl.gov> <3EF0C5FA.302@centtech.com> <3EF0CADD.B096A242@lbl.gov> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: freebsd-performance@freebsd.org Subject: Re: freebsd-performance Digest, Vol 4, Issue 7 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: Wed, 18 Jun 2003 20:44:28 -0000 Jin Guojun [DSD] wrote: > Eric Anderson wrote: > > >>>Very minimum. >>>It was slow on SCSI bus , but I do not have time to diagnose, >>>which can be very time consuming. >> >>My tests have shown that a GOOD hardware RAID5 controller can really >>help you out when it's being slammed (specially over NFS) - I use Dell >>PERC/2 and PERC/3 controllers (rebranded AMI RAID boards). They run >>like champs, and I get 40MB/s sustained xfers.. > > > What did you mean sustained xfers ? -- in and out, or just read out. sustained writes (not burst transfers) and sustained reads.. With hardware RAID's that have cache memory on them (as the PERC's do - mine has 128mb), you can get huge burst speeds (all in memory, so it makes sense). If you have a machine that is writing small files constantly, the cache can significantly help. However, putting a lot of extra memory in the server running a software RAID can do this with similar results. I always suggest piling on the RAM for servers.. Eric -- ------------------------------------------------------------------ Eric Anderson Systems Administrator Centaur Technology Attitudes are contagious, is yours worth catching? ------------------------------------------------------------------