Date: Mon, 23 Feb 1998 08:48:50 +1030 From: Greg Lehey <grog@lemis.com> To: Jan Koum <jkb@best.com>, FreeBSD Questions <questions@FreeBSD.ORG> Subject: Re: How can I mirror a FreeBSD hard drive? Message-ID: <19980223084850.45183@freebie.lemis.com> In-Reply-To: <Pine.BSF.3.96.980222000711.27821A-100000@shell6.ba.best.com>; from Jan Koum on Sun, Feb 22, 1998 at 12:09:13AM -0800 References: <19980222183356.17059@freebie.lemis.com> <Pine.BSF.3.96.980222000711.27821A-100000@shell6.ba.best.com>
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On Sun, 22 February 1998 at 0:09:13 -0800, Jan Koum wrote: > On Sun, 22 Feb 1998, Greg Lehey wrote: > >> On Sun, 22 February 1998 at 0:01:03 -0800, Jan Koum wrote: >>> On Thu, 19 Feb 1998, Greg Lehey wrote: >>> >>>> On Wed, 18 February 1998 at 20:51:15 -0500, Brad wrote: >>>>> >>>>> To Whom It May Concern, >>>>> >>>>> I have a full, working, beautiful install of FreeBSD. It is now time for >>>>> it to go on the Internet. However, there is one thing that I still would >>>>> like to do. This machine has 2 hard drives in it. The first drive is the >>>>> whole FreeBSD install. The second drive is totally unused. I would like >>>>> to mirror the FreeBSD drive to the unused drive so that in the event of a >>>>> crash, I can just switch the jumpers and the backup drive becomes the >>>>> master, bootable FreeBSD drive and things carry on as normal. >>>> >>>> Well, the only way you can currently do this is with the ccd driver. >>>> It's not as simple as it sounds, though: >>>> >>>> 1. You can't mirror the root file system. >>>> 2. If one of your drives goes down, you need to reboot and >>>> reconfigure to use the other one. >>> >>> Could you use 'dd' though? >> >> You wouldn't need to. The data's there, but CCD is too stupid to come >> up if one of its components is down, so you have to remove that >> component from the config. This bug could be fixed, of course, but >> there are plenty more like it, and I've got better things to do. > > No, what I mean is, can I just use dd? For example, I have two > scsi drive, and I would just 'dd if=/dev/sd0 of=/dev/sd1 bs=8192' every > week or so. Then if my sd0 dies, I should have no problem to use sd1? Just > would have to change adaptec's boot device to the new scsi disk. Or is it > more complicated than I think? (like, where kernel/boot/etc would look?) The disk driver includes some safety measures which make it difficult to write a complete disk. I believe there is a way, but I never got it to work. Anyway, there's no need. There are plenty of utilities (tar, cp) which will replicate file systems on a different file system. Greg To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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