From owner-freebsd-questions Tue Feb 10 20:14:34 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id UAA08370 for questions-outgoing; Tue, 10 Feb 1998 20:14:34 -0800 (PST) (envelope-from owner-freebsd-questions@FreeBSD.ORG) Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id UAA08147 for ; Tue, 10 Feb 1998 20:13:53 -0800 (PST) (envelope-from grog@lemis.com) Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by allegro.lemis.com (8.8.7/8.8.5) with ESMTP id OAA16931; Wed, 11 Feb 1998 14:34:23 +1030 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.8.8/8.8.7) id OAA21001; Wed, 11 Feb 1998 14:34:01 +1030 (CST) (envelope-from grog) Message-ID: <19980211143401.15932@freebie.lemis.com> Date: Wed, 11 Feb 1998 14:34:01 +1030 From: Greg Lehey To: Robert Eckardt , dwhite@resnet.uoregon.edu Cc: perl@netmug.org, freebsd-questions@FreeBSD.ORG Subject: Re: ccd mirroring References: <199802042340.AAA00646@ghost.mep.ruhr-uni-bochum.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.89i In-Reply-To: <199802042340.AAA00646@ghost.mep.ruhr-uni-bochum.de>; from Robert Eckardt on Thu, Feb 05, 1998 at 12:40:12AM +0100 WWW-Home-Page: http://www.lemis.com/~grog Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Thu, 5 February 1998 at 0:40:12 +0100, Robert Eckardt wrote: > It was Doug White who wrote: >> On Tue, 3 Feb 1998, Michael Haro wrote: >> >>> I was reading about ccd and how it can be used to mirror data kinda like >>> RAID level 1. >>> >>> If one of the drives crash, how would I remedy the crash? >>> The drives I currently have are different sizes, would this cause a >>> problem when using ccd? >> >> Yes, it's not permitted. CCD must use homogenous disks. >> >> Recovering a mirrored disk involves bringing over a disklabel and fixing >> some other bits. It's not a seamless recovery, but the data is still >> there. I'm not familiar with the entire procedure but someone probably >> figured it out at some point and posted about it :) > > A while ago, I had this problem. > One of my mirrored disks produced more and more read errors until > it effectively stopped working. > > All I had to do was to reconfig ccd to use only one disk as a > "mirrored" ccd disk. That's the way you have to do it. But I wouldn't say "all". > BTW, a question: I understand that for mirroring ccd writes > data on both disks "simultaneously". > But what about reading ? It reads the first component of the pair. Every time. > Will it catch inconsistencies between the two disks ? No. That would be an inefficient way to do things, too. Greg To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe questions" in the body of the message