From owner-freebsd-questions@FreeBSD.ORG Thu Oct 28 04:20:08 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2E98816A4CE for ; Thu, 28 Oct 2004 04:20:08 +0000 (GMT) Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.207]) by mx1.FreeBSD.org (Postfix) with ESMTP id BE56743D55 for ; Thu, 28 Oct 2004 04:20:07 +0000 (GMT) (envelope-from nomadlogic@gmail.com) Received: by wproxy.gmail.com with SMTP id 68so409714wri for ; Wed, 27 Oct 2004 21:20:03 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:references; b=ikrKSLx8huYw6Mf48rZskKHTnko43g1UBI7hnZQSh7GGcpLB2wrOMNm9prOYJfezIJSKDJPAFzh/ky6JldezMl6wwqZKtg4OE96jgGDP9zf0xUMK7QK+e5EZmbUXcnaCz3x640wWTlL8RybBzJK6PnN2MeSC2pSRX7GN5fw0Osw= Received: by 10.38.82.27 with SMTP id f27mr1619954rnb; Wed, 27 Oct 2004 21:20:03 -0700 (PDT) Received: by 10.38.14.69 with HTTP; Wed, 27 Oct 2004 21:20:03 -0700 (PDT) Message-ID: <57d710000410272120157172a4@mail.gmail.com> Date: Wed, 27 Oct 2004 21:20:03 -0700 From: pete wright To: "Thordur I." In-Reply-To: <412FAA46.70105@mi.is> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable References: <412FAA46.70105@mi.is> cc: questions@freebsd.org Subject: Re: Software or hardware RAID1. (gstripe) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: pete wright List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 Oct 2004 04:20:08 -0000 On Fri, 27 Aug 2004 21:40:22 +0000, Thordur I. wrote: > I=B4m currently trying to decide upon a sultion on how to go about keepin > my data safe. >=20 > Now, a RAID1 setup sounds good in this position. But I can=B4t seem to > find an answer to one question. >=20 > Let=B4s say that I have 2x 120Gb (ad1 and ad2) disk. I stripe them wich > should give something like /dev/stripe/foo (either with gstripe or a > hardware raid controler.) >=20 > Now I fill this striped volume with data, and ad1 dies. > What happen=B4s ? > Does gstripe alert my that ad1 has died and will I still be able to > access /dev/stripe/foo ? > And when I shut the box down, remove ad1 and insert another (identical > disk) to restore the stripe, what then ? (assume the same bus ofcourse) >=20 > I have tryed to google this up but to no avail. >=20 > Any help is well appriceated. >=20 here is a good link regarding raid levels in general http://www.acnc.com/04_01_00.html what it sounds like is you want to create a mirror of disks for maximum data integrity. depending on how much disk i/o you are going to be doing i think using a hardware RAID solution on one level or another is probably the best choice. not only does it free the OS up from having to manage the RAID but you also gain benefits of onboard cache of the disk controllers, and if you are lucky decent management firmware to maintain the array(add new disks, verification, etc). the idea with striping is to be able to survive a failure of one of the disks while being reasonably sure that the data integrity on those disks will be intact. most hardware raid controllers will alert you when a disk fails, as i'm sure gstripe will as well altho i have not used it personally. the next step is rebuilding, this is usually also managed by the hardware controller or via the RAID implementation on the OS level (vinum etc..) and should be automatic when a new working disk is available. If you are lucky to have hot-swapable disks a power cycle is not even neccessary. now if you have the money/space for multiple disks you it may worth looking at RAID 5, which will give you decent i/o and decent fault tolerance. or you can start playing with stripping disks togther in LUN's then mirroring set's of the LUN's together but that is usually an expensive route (for disks, controllers and high-speed interconnects). as always the specific man pages for which ever implementation are the best sources for info. HTH -p --=20 ~~o0OO0o~~ Pete Wright www.nycbug.org NYC's *BSD User Group