From owner-freebsd-questions@FreeBSD.ORG Fri Nov 23 09:21:54 2007 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3D05B16A4DA for ; Fri, 23 Nov 2007 09:21:54 +0000 (UTC) (envelope-from j.catrysse@proximedia.be) Received: from smtp.proximedia.com (popop.online.be [194.88.108.79]) by mx1.freebsd.org (Postfix) with ESMTP id EABA113C448 for ; Fri, 23 Nov 2007 09:21:53 +0000 (UTC) (envelope-from j.catrysse@proximedia.be) Received: from TEC04 (unknown [194.88.104.244]) by smtp.proximedia.com (Postfix) with ESMTP id E0E1B2878E; Fri, 23 Nov 2007 10:21:46 +0100 (CET) From: "Jan Catrysse" To: Date: Fri, 23 Nov 2007 10:25:26 +0100 Organization: Proximedia Belgium S.A. MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Mailer: Microsoft Office Outlook, Build 11.0.5510 In-Reply-To: <20071122155640.fa7e0536.wmoran@potentialtech.com> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 Thread-Index: AcgtS4P5gI4jNn2uSUuopsMz9TvfFgAY7AKg Message-Id: <20071123092146.E0E1B2878E@smtp.proximedia.com> Cc: 'Bill Moran' Subject: RE: RAID1 synchronisation - howto OR not necessary? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 23 Nov 2007 09:21:54 -0000 > From: Bill Moran [mailto:wmoran@potentialtech.com]=20 > Sent: Thursday, November 22, 2007 9:57 PM > To: Jan Catrysse > Cc: freebsd-questions@freebsd.org > Subject: Re: RAID1 synchronisation - howto OR not necessary? >=20 > "Jan Catrysse" wrote: > > > > Dear subscribers, > >=20 > > I am currently running a production server: > > FreeBSD 6.2 STABLE > > Onboard Intel ICH8R Raid 1 with 2x SATA300 500GB HDD Using ATA for=20 > > Raid1 > >=20 > > On Windows systems it is an absolute must to do a Raid=20 > Synchronisation=20 > > every once and a while to maintain data consistency. >=20 > Wow. Any RAID controller with that requirement is junk. =20 > Where did you get the information from that you had to=20 > synchronize? Does it say so in the manual? Does it actually=20 > say "every once and a while" or does it give a specific schedule. >=20 > I suspect that you have wrong information ... but if your=20 > information is correct, I'd get a refund on that RAID controller. >=20 > > I am some what disturbed that that kind of command / tool seems not=20 > > available on FreeBSD. >=20 > There is not, because such a thing should not be necessary. >=20 > > Are there other methods to do the synchronisation? > > 1) Maybe atacontrol detach & atacontrol addspare &=20 > atacontrol rebuild? > > 2) Maybe data consistency is always maintained automatically by the=20 > > driver? > > 3) Maybe I have to panic and urgently make backups? >=20 > If resyncing your raid on a regular basis is truly a=20 > requirement, I'd do > #3 at least, followed by getting my money back. Hi Bill, Thank you for your input. I assumed this was common knowledge, but I can be wrong? I've checked some other RAID controllers in the company and all of them = have the need to be verified/synchronized once and a while. This happens = in the BIOS for the more expensive cards (> 600=E2=82=AC) and with a = utility/driver for the low budget cards... In my case I am using a real inexpensive onboard Intel ICH8R controller = but I presume even a low cost controller needs to do the job done. = Furthermore it's only a simple mirror... Intel provides a small windows = utility to synchronize. This is what I found in a 3Ware manual: Verification can provide early warning of a disk drive problem or = failure. ...verification once every 24 hours... Not verifying the unit periodically can lead to an unstable array unit = and may cause data loss. It is strongly recommended that you schedule a verify at least 1 time = per week. For a RAID 1 or RAID 10 unit, a verify compares the data of one mirror = with the other. For RAID 5, RAID 6, and RAID 50, a verify calculates = parity and compares it to what is written on the disk drive. Cheers, Jan