Date: Tue, 18 Jan 2005 18:21:48 -0600 From: Craig Boston <craig@feniz.gank.org> To: Greg 'groggy' Lehey <grog@FreeBSD.org> Cc: David Elsing <davidelsing@gmail.com> Subject: Re: Vinum Raid5 Init question Message-ID: <20050119002148.GA1328@nowhere> In-Reply-To: <20050118232525.GW79181@wantadilla.lemis.com> References: <bfd7e89b05011803213642895c@mail.gmail.com> <20050118143302.GA99345@nowhere> <20050118232525.GW79181@wantadilla.lemis.com>
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On Wed, Jan 19, 2005 at 09:55:25AM +1030, Greg 'groggy' Lehey wrote: > Yes, it could be clearer. Put in a PR. I'm more than willing to submit a patch if it will help, but will it do any good this late in the release cycle? Especially if there will be no 4.12 release. > > Also, if a good disk gets marked as "down" somehow before you can > > correct this, whatever you do, do NOT issue a "vinum start" command > > on it. In the current state of the array, that would be destructive > > and irreversible. > > No, that's the correct way to do it. Normally it would be, yes. However in this case (at least it was for me), all of the normal blocks are fine, but the parity blocks are random garbage since init was never run. If a drive goes into the "down" state for some reason but is physically fine, starting the subdisk will begin "reconstructing" the data from the bogus parity, wiping out any hope of recovering the good data. If a drive does get detached somehow, it's likely that the system won't stay up very long -- from its point of view at least one filesystem has suddenly become very corrupt. The setstate is dangerous and will probably result in a somewhat inconsistent filesystem, but it's still preferable to a total loss... > I can't recall seeing a problem report. There wasn't one. I had encountered the problem on several machines in a short timespan (fortunately only one had anything important) so I asked you about in in private mail. I didn't think the problem was with FreeBSD or vinum itself -- it was more of a "what am I doing wrong?" question. After a couple rounds you determined that it was likely I hadn't run vinum init, and sure enough that's what it was. Sorry, I can't provide a time reference. At the time of the exchange my mail archive was down (that's what was on the doomed filesystem :). Craig
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