From owner-freebsd-questions@FreeBSD.ORG Mon Jul 26 21:11:27 2010 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 774BA1065673 for ; Mon, 26 Jul 2010 21:11:27 +0000 (UTC) (envelope-from Ggatten@waddell.com) Received: from mailhost0.waddell.com (mailhost0.waddell.com [12.154.38.61]) by mx1.freebsd.org (Postfix) with ESMTP id 395978FC0C for ; Mon, 26 Jul 2010 21:11:26 +0000 (UTC) Received: from emlpfilt4.waddell.com (mailhost.waddell.com [10.1.10.26]) by mailhost0.waddell.com (Postfix) with ESMTP id B5C10265C28 for ; Mon, 26 Jul 2010 15:41:20 -0500 (CDT) Received: from emlpfilt4.waddell.com (localhost [127.0.0.1]) by localhost (Postfix) with SMTP id A6F052F8001 for ; Mon, 26 Jul 2010 15:41:20 -0500 (CDT) Received: from ADVPHTCAS0.wradvisors.com (advphtcas0.wradvisors.com [192.168.203.228]) by emlpfilt4.waddell.com (Postfix) with ESMTP id 9C74A578846 for ; Mon, 26 Jul 2010 15:41:20 -0500 (CDT) Received: from WADPMBXV0.waddell.com ([169.254.1.108]) by ADVPHTCAS0.wradvisors.com ([192.168.203.228]) with mapi; Mon, 26 Jul 2010 15:41:20 -0500 From: Gary Gatten CC: "freebsd-questions@freebsd.org" Date: Mon, 26 Jul 2010 15:41:19 -0500 Thread-Topic: 1 file system, 2 drives? Thread-Index: AcstAZvKD11I96c1QrmbduSR4p5WyAAAEPjg Message-ID: <29133_1280176880_4C4DF2F0_29133_203_1_D9B37353831173459FDAA836D3B4349968A910AE@WADPMBXV0.waddell.com> References: <4C4DDA28.4070205@identry.com> <980022A0-7623-40A5-BCDE-4909A721933D@mac.com> <4C4DF067.7000801@identry.com> In-Reply-To: <4C4DF067.7000801@identry.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: RE: 1 file system, 2 drives? 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: Mon, 26 Jul 2010 21:11:27 -0000 >From my experience (YMMV), most RAID controllers will NOT redistribute the = existing data/files onto the newly added drives. So, if you have a (3) dri= ve RAID5 your file exists on all three drives, as does the parity data. If= you add (2) drives, your original files will not be on the new drives. Ne= w files WILL use all (5) drives. IMHO it's best to backup the data (twice)= , create a new volume on the new RAID, and restore the data. That said, ma= ybe better/newer RAID controllers will redistribute / balance existing data= across all drives in the array - I don't know for sure. Either way, backu= p your data - twice! And make sure it can be restored! Just because the b= ackup app SAYS it's OK, it's NOT OK until it can be successfully restored! Also, if you go from (7) drives to (3), your I/O may suffer. Newer faster = drives MAY make up the difference, or make up enough of it that it won't im= pact your client. Just be aware this is a potential issue. Generally spea= king more spindles =3D more I/O's / sec. G -----Original Message----- From: owner-freebsd-questions@freebsd.org [mailto:owner-freebsd-questions@f= reebsd.org] On Behalf Of John Almberg Sent: Monday, July 26, 2010 3:31 PM To: Chuck Swiger Cc: freebsd-questions@freebsd.org Subject: Re: 1 file system, 2 drives? > If you have hardware controller with RAID capabilities, using native RAID= is better, otherwise look towards gvinum or maybe ccd; see also: >=20=20=20=20 I've just been reading up on RAID in my Absolute FreeBSD book, and it=20 occurs to me that my client has a SCSI RAID drive chassis that he is=20 using stupidly... It's a 14 bay drive, and he's currently got seven 32G drives stuck in=20 it, configured with RAID-0. This is the original 200G drive I was=20 talking about. It's a few years old. Over the next few years, this guy is going to need lots of storage for=20 his videos. After a bit of reading, I'm wondering if the best idea might be to toss=20 out those 32G drives and replace them with 3 big (say, 300G) drives=20 configured with RAID-5. It sounds to me like a RAID-5 array can be=20 expanded by adding new drives. QUESTION: is expansion normally a matter of just plugging in a new=20 drive? Is the new drive automatically grafted onto the old drives? Or do=20 you have to go through a process like, backing up the data, plugging in=20 the new drive, reformatting the expanded array of drives, and restoring=20 the data. I don't know the brand/model of the RAID drive chassis, but the client=20 thinks it can be switched to use RAID 5. I'm waiting for the technical=20 details, but assuming it can handle RAID-5 for now. Thanks: John _______________________________________________ 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"
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