Date: Thu, 11 Feb 2016 12:11:03 +0100 From: Polytropon <freebsd@edvax.de> To: Ian Smith <smithi@nimnet.asn.au> Cc: freebsd-questions@freebsd.org Subject: Re: fsck is failing to clean a filesystem Message-ID: <20160211121103.40cb3a9b.freebsd@edvax.de> In-Reply-To: <20160210204635.K51785@sola.nimnet.asn.au> References: <mailman.107.1455019202.84699.freebsd-questions@freebsd.org> <20160210160149.V51785@sola.nimnet.asn.au> <C974C8D0-37C0-4708-9F1A-6CDC4716A8D4@gmail.com> <20160210195431.V51785@sola.nimnet.asn.au> <20160210102236.19f9c68c.freebsd@edvax.de> <20160210204635.K51785@sola.nimnet.asn.au>
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On Wed, 10 Feb 2016 21:56:48 +1100 (EST), Ian Smith wrote: > On Wed, 10 Feb 2016 10:22:36 +0100, Polytropon wrote: > > On Wed, 10 Feb 2016 20:11:03 +1100 (EST), Ian Smith wrote: > > > On Tue, 9 Feb 2016 22:10:14 -0800, Paul Beard wrote: > > > > > > Well at least /usr/src is easily replaced. Might be worth just deleting > > > all that, though of course you need a read-write mount first .. perhaps > > > after booting from a memstick or live CD? > > > > Which is still risky, assuming that the file system has not > > been marked clean. > > Absolutely. I'm assuming that at this stage the choice is to newfs /usr > and restore backups, unless some magic spell turns up. Once apparently > losing or damaging '..' from anywhere, you're pretty much in trouble. Yes, running newfs on that particular file system should be the easiest way to deal with a file system damage like that. > Paul, another question: with /usr unmounted, is there anything in /usr ? Hmmm... fsck /usr operates on the /usr partition (or to be correct, on the device associated with it), but when the mountpoint itself (the directory /usr, residing on /) is "contamined", it might cause trouble later on, when the partition has been mounted. So any mountpoint should be checked for being an empty directory. > > > Just stabbing in the dark .. scrambled filesystems are the pits! > > > > And a good occassion to read more about UFS (McKusick et al.) - to > > develop a better understanding of what's happening. :-) > > Good suggestion :) I envy people who've got the time these days .. I had the chance and opportunity to do so, when a massive file system damage caused a significant data loss. This drove me to this mailing list, and finally, I got _all_ my data back. The actual loss was a few hundred directory names and a few thousand file names, which is not a big problem thanks to file magic based sorting tools. However, a good understanding of file system internals is helpful to avoid excessive spendings on data recovery. Sure, you can "trust the experts" and pay $5000-10,000, and maybe they then say: "Sorry, norhing to recover", or you can buy expensive software for "trial & error". It finally boils down to a "money vs. time" consideration. I decided to invest my time to learn some UFS, and it saved my ass. :-) -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...
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