Date: Wed, 2 Sep 2009 10:33:24 +0200 From: Thomas Backman <serenity@exscape.org> To: Mark Stapper <stark@mapper.nl> Cc: freebsd-stable@freebsd.org, Emil Mikulic <emikulic@gmail.com>, Miroslav Lachman <000.fbsd@quip.cz>, Maciej Jan Broniarz <gausus@gausus.net> Subject: Re: zfs on gmirror slice Message-ID: <DB79F60C-1F6F-4605-A39C-F916E20796B4@exscape.org> In-Reply-To: <4A9E2C7C.6030904@mapper.nl> References: <a7454e2f0909010704g2fb27216hacb3ffd2cae5594c@mail.gmail.com> <061541E3-F301-46C4-8ECB-5B05854F0EAA@exscape.org> <a7454e2f0909010904s224be2ectdd18eb887f4c1311@mail.gmail.com> <4A9D558A.9070609@quip.cz> <4A9E1CB5.6030906@mapper.nl> <20090902074445.GA13588@dmr.ath.cx> <4A9E2C7C.6030904@mapper.nl>
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On Sep 2, 2009, at 10:27 AM, Mark Stapper wrote: > Emil Mikulic wrote: >> On Wed, Sep 02, 2009 at 09:20:21AM +0200, Mark Stapper wrote: >> >>> updating a zfs filesystem which you are running from is next to >>> impossible. >>> >> >> [citation needed] :) >> > Well, to update your zfs filesystem version, the filesystem is first > unmounted, then updated, and then mounted again. > citation coming up! > # umount / > umount: unmount of / failed: Invalid argument Nothing a LiveCD or something to that regard can't handle. Obviously this doesn't work for everyone, but it should for many. >> >>> So, i would recommend setting up gmirror to mirror your whole disks, >>> install the base system(boot and "world") on a small UFS slice, >>> and use >>> the rest of the disc as zfs slice. >>> >> >> As Thomas Backman pointed out, this means you won't get self-healing. >> > self-healing sounds very nice, but with mirrorring you have data on > two > discs, so in that case there no "healing" involved, it's just > checksumming and reading the non-corrupted copy. > From the gmirror manpage: "All operations like failure detection, > stale > component detection, rebuild of stale components, etc. are also done > automatically." > This would indicate the same functionality, with a much less fancy > name. > However, i have not tested it the way they demonstrate zfs's > "self-healing" property. > I might, if I get the time to run it in a virtual machine one of these > days.. If ZFS finds a corrupted copy and a non-corrupted one in a mirrored ZFS pool, it will repair the damage so that both copies are valid, so yes, self-healing will indeed occur. :) Regards, Thomas
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