From owner-freebsd-questions@FreeBSD.ORG Sun Jan 25 21:24:47 2009 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 E99101065687 for ; Sun, 25 Jan 2009 21:24:46 +0000 (UTC) (envelope-from josh@tcbug.org) Received: from out3.smtp.messagingengine.com (out3.smtp.messagingengine.com [66.111.4.27]) by mx1.freebsd.org (Postfix) with ESMTP id BE8B48FC1D for ; Sun, 25 Jan 2009 21:24:46 +0000 (UTC) (envelope-from josh@tcbug.org) Received: from compute1.internal (compute1.internal [10.202.2.41]) by out1.fastmail.fm (Postfix) with ESMTP id 8BD36257B1A; Sun, 25 Jan 2009 16:14:38 -0500 (EST) Received: from heartbeat2.messagingengine.com ([10.202.2.161]) by compute1.internal (MEProxy); Sun, 25 Jan 2009 16:14:38 -0500 X-Sasl-enc: wvO//LaNm9QNSakd8QurtCx0egEj/Hg4dd8lzoC6T8ZN 1232918078 Received: from roadrash.tcbug.org (ip70-181-6-240.ri.ri.cox.net [70.181.6.240]) by mail.messagingengine.com (Postfix) with ESMTPSA id 090282DAFD; Sun, 25 Jan 2009 16:14:37 -0500 (EST) Message-ID: <497CD63D.8010308@tcbug.org> Date: Sun, 25 Jan 2009 16:14:37 -0500 From: Josh Paetzel User-Agent: Thunderbird 2.0.0.19 (Macintosh/20081209) MIME-Version: 1.0 To: Omer Faruk Sen References: <75a268720901251042p67515b92kda61bc875dcdab97@mail.gmail.com> In-Reply-To: <75a268720901251042p67515b92kda61bc875dcdab97@mail.gmail.com> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-questions@freebsd.org Subject: Re: atacontrol software or hardware raid X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: josh@tcbug.org List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 25 Jan 2009 21:24:47 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Omer Faruk Sen wrote: > How can I detect if system has Software or hardware raid? Since in manual page: > > The atacontrol command can also be used to create purely software RAID > arrays in systems that do NOT have a "real" hardware RAID card such as a > Highpoint or Promise card. A common scenario is a 1U server such as the > HP DL320 G4 or G5. These servers contain a SATA controller that has 2 > channels that can contain 2 disks per channel, but the servers are wired > to only place a single SATA drive on each channel. > > Or how can I find out if the hardware is "real" hardware RAID card? > For example my system has following dmesg output: > > ad4: 152627MB at ata2-master SATA300 > ad6: 152627MB at ata3-master SATA300 > ar0: 152625MB status: READY > ar0: disk0 READY (master) using ad6 at ata3-master > ar0: disk1 READY (mirror) using ad4 at ata2-master > > This system is an intel server with S3210SH server board in it. While > installing system I see ad4,ad6 and ar0 as harddrives in sysinstall. I > choose to install ar0. > > Additionally as far as I see ar0 is very susceptible to errors since a > single CRC error can break the RAID consistency is that normal? I > really appreciate those who uses such a kind of RAID1 > > Regards. > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" ar RAID devices are almost always software/BIOS RAID. In this case intel matrix raid is software RAID provided by the system BIOS. The disadvantages of using it is your RAID array isn't portable to machines that don't have the same BIOS raid implimentation. One of the advantages of BIOS RAID is that you can boot from stripes, which you aren't doing anyways. You'll probably find that disabling the motherboard RAID and creating a gmirror device is a better option for software RAID 1. - -- Thanks, Josh Paetzel PGP: 8A48 EF36 5E9F 4EDA 5ABC 11B4 26F9 01F1 27AF AECB -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (Darwin) iEYEARECAAYFAkl81jYACgkQJvkB8Sevrsu1swCcCCq6/cG0WYajBvutibgvhIaA kn8An27y/SPbEKzRyaWntfZV95z/UJia =k2Gx -----END PGP SIGNATURE-----