From owner-freebsd-hardware Tue Mar 27 15:26: 5 2001 Delivered-To: freebsd-hardware@freebsd.org Received: from ftp.nvg.com (ftp.nvg.com [199.179.254.6]) by hub.freebsd.org (Postfix) with ESMTP id D0E3D37B718; Tue, 27 Mar 2001 15:25:59 -0800 (PST) (envelope-from Ed.Henderson@Certainty.net) Received: from pnt004 (vsat-148-63-55-208.c1.sb4.mcl.starband.net [148.63.55.208]) by ftp.nvg.com (8.9.3+Sun/8.9.3) with SMTP id SAA11056; Tue, 27 Mar 2001 18:19:30 -0500 (EST) From: "Ed Henderson" To: "'Michael VanLoon'" , "'Andrew C. Hornback'" , "'Joseph Gleason'" Cc: "'FreeBSD Hardware'" , "'Mike Smith'" Subject: RE: Server MB suggestions? Date: Tue, 27 Mar 2001 18:19:00 -0500 Message-ID: <003101c0b714$4ec47260$0464a8c0@pnt004> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 In-reply-to: Importance: Normal Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org OK, OK!!! I give in I'm going SCSI (small cheer from the cheap seats!). = Here is what I'm going to use: 1. Lets assume for now that I will use a standard 2 channel SCSI = controller (non-RAID) and will use software RAID-1 with one 36GB drive = on each channel. Any controller recommendations? 2. What drives do you recommend - manufacturer, model. 3. Should I go for 160MB/s or stick with 80MB/s drives? I am trying to = be reasonable in cost. 4. I plan to have an external DDS-4 DAT tape drive attached to one of = the channels. Any suggestions? Many thanks to all contributors! Ed. >=20 > I think you have that backwards. Reading mirrors, with a=20 > good controller, > increases performance, not decreases. A good hardware RAID=20 > controller will > interleave read requests from mirrored drives so you can=20 > approach double the > read throughput of a single drive. >=20 > And writes should be the same speed (roughly) writing to two=20 > drives as one, > since they're simultaneous. Of course in reality, bus=20 > bandwidth comes into > play, and is one of the reasons lots of installations install=20 > each pair of > mirrored drives on separate SCSI busses. >=20 > Here are the benefits of SCSI hardware RAID over IDE RAID: >=20 > - More performance with lots of drives, both because you can have more > drives on more busses, and because the RAID is actually=20 > happening on the > controller (many IDE "hardware" RAID controllers do only the=20 > basic work > needed, and much is still done in the BIOS or the OS). >=20 > - More extensible. With a 3-bus SCSI controller you can hang up to 45 > devices off it. It's pretty easy to max out an IDE RAID=20 > controller and have > nowhere to go. >=20 > - More easily extensible. A good hardware RAID controller=20 > will allow you to > do dynamic expansion of the volume. I.e., throw a couple=20 > more drives on, > tell the controller to expand it, it does so in the=20 > background, rearranging > the pieces of the array for optimum performance, and viola, you have a > larger virtual drive. Then you just need to use the OS to=20 > either expand the > filesystem/partition (i.e. growfs), or add a new one. >=20 > - Reliability. SCSI drives are simply more reliable. IDE=20 > drives are made > with cost as the primary requirement. They fail more often. =20 > Please don't > flame me on this. Yes, SCSI drives fail, and yes lots of IDE=20 > drives last a > long time, but over a large sample, it's pretty much a fact=20 > that IDE drives > have more failures than SCSI drives. >=20 > On the other hand, yes modern IDE drives are fairly well=20 > built, pretty fast, > and cheap cheap cheap. Balance as your needs, comfort level=20 > and budget can > accommodate. >=20 > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hardware" in the body of the message >=20 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message