Date: Mon, 11 Aug 2014 03:09:07 +0200 From: Roland Smith <rsmith@xs4all.nl> To: David Benfell <benfell@parts-unknown.org> Cc: Polytropon <freebsd@edvax.de>, freebsd-questions@freebsd.org Subject: Re: operation not permitted on entropy file Message-ID: <20140811010907.GA1273@slackbox.erewhon.home> In-Reply-To: <20140810224038.GD24036@home.parts-unknown.org> References: <20140810070239.GA80734@home.parts-unknown.org> <20140810103119.GA26958@slackbox.erewhon.home> <20140810124433.da498898.freebsd@edvax.de> <20140810224038.GD24036@home.parts-unknown.org>
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--x+6KMIRAuhnl3hBn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Aug 10, 2014 at 03:40:39PM -0700, David Benfell wrote: > > > Trying to make a backup in this state will probably not work. > >=20 > > Maybe files cannot be read, or are improperly read (and therefore > > wrongly represented in the backup). When I do backups, I usually > > make sure two things: 1st, the file system is _clean_, 2nd, the > > file system is protected against alteration (r/o mount, or not > > mounted at all). Definitely. > I know there are "snapshots" (as they exist in > > relation with fsck, too), but I don't trust them. Many years ago, > > such a snapshot made it _impossible_ for fsck to do its job. Once > > it was removed, I got my files back (for the price of a few lost > > file names, but still better than nothing). A problem surfaced in the 8.x - 9.x timeframe where dump(8)-ing a live filesystem (which is done via a snapshot) would hang. At that time the advi= ce was to not make live dumps but to make dumps in single user mode. I'm not sure if the problem was found and rectified yet. I've been making dumps in single user mode ever since, just to be safe. > Perhaps I misunderstand. I thought journaling was supposed to > *increase* the robustness of a filesystem. It seems to me that what > this amounts to is the contrary. Well, UFS (a.k.a. ffs(7) ) doesn't have journaling as such. It does have journaling[1] for *soft updates[2]*. The basic purpose of journaling in this case is to reduce the time to run an fsck. And that works very well. When making backups I drop my system to single user mode and every now and then I run a *full* fsck of every filesystem before running dump(8). But I must say that this usually doesn't find serious problems. The only re= al causes of filesystem corruption that I have encountered have basically been; * dying HDDs * repeated crashes (often also hardware related; memory, power supply, overheating) [1]: http://www.mckusick.com/BSDCan/bsdcan2010.pdf [2]: http://en.wikipedia.org/wiki/Soft_updates Roland --=20 R.F.Smith http://rsmith.home.xs4all.nl/ [plain text _non-HTML_ PGP/GnuPG encrypted/signed email much appreciated] pgp: 5753 3324 1661 B0FE 8D93 FCED 40F6 D5DC A38A 33E0 (keyID: A38A33E0) --x+6KMIRAuhnl3hBn Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJT6BezAAoJEED21dyjijPg0UYP/3zFvE2Lr3dpHIsCJU32uq0K jsD9zh20iD/JrZ6oHxa03h7qW4XMRm2qHxRN2pkyorb98hruPEJ0V3Zag/EAbpSi uUyq417kw1GPPPkMjo5ArBOcvooFsi8/Yk6vCM9xL13oWP91QQT/8cnzJ8dBlw0T yiFWqB0/JZ8EEW78beuLuXost0FCmCodP/DXm+m5JHkv2F0e8/FCV3uxyy+n0Epa jqdnW1zOGmSsEYFlw7phxE1xrutd4R+l+JWEP4uDtyblal6g4EIcjrKappsBDaOB LYEBNIwO43mWUZvINensb1d4Qp9dIvcNgoYCq+XI4zzmRKHT6AKp27TUzF2RQ1Ho Txq73efkFKRzTToaReS2nsmOO5RjRmpNl+DGWCdc7SYYn8Xs36NIaKoMEBI13a73 1EHOsFmL6K85qmThXqweulosfhk/HHsRREuFojutBZMWGP2M+sc6sg9KNQPP5xiw Z7wWnKNfhwissryx4VerChZvOUqVxuTKxn2aUUY2BDK0g9nAqf0HlJ/DzM/PLkLr eKjBEgWqk9WVBY0KgKKK58fQn/fJNw7zKi6ewMSQASMlJCmSsZeHJrDERnWtfTRH 4TehSH9ncTs6lUoGeWlzha9rNoytJshd+yEmOlbwTY7zQ+CFY6aPpX6hB2wPd8QS 87Kt+Lkwg8IRogQxOF1j =xeyh -----END PGP SIGNATURE----- --x+6KMIRAuhnl3hBn--
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