Date: Wed, 11 Feb 1998 14:34:01 +1030 From: Greg Lehey <grog@lemis.com> To: Robert Eckardt <roberte@MEP.Ruhr-Uni-Bochum.de>, dwhite@resnet.uoregon.edu Cc: perl@netmug.org, freebsd-questions@FreeBSD.ORG Subject: Re: ccd mirroring Message-ID: <19980211143401.15932@freebie.lemis.com> In-Reply-To: <199802042340.AAA00646@ghost.mep.ruhr-uni-bochum.de>; from Robert Eckardt on Thu, Feb 05, 1998 at 12:40:12AM %2B0100 References: <Pine.BSF.3.96.980204123341.15689H-100000@gdi.uoregon.edu> <199802042340.AAA00646@ghost.mep.ruhr-uni-bochum.de>
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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
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