Date: Thu, 13 Nov 2008 10:57:44 -0600 From: Kevin Day <toasty@dragondata.com> To: =?ISO-8859-1?Q?Javier_Mart=EDn_Rueda?= <jmrueda@diatel.upm.es> Cc: freebsd-fs@freebsd.org Subject: Re: UFS Snapshot lock time Message-ID: <CCDF25A5-3933-4F08-B39E-1BDF2D4DCDA5@dragondata.com> In-Reply-To: <491C51A7.8080000@diatel.upm.es> References: <6EEFB17C-10DF-4CCD-AB07-83B4B75D033F@dragondata.com> <491C51A7.8080000@diatel.upm.es>
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On Nov 13, 2008, at 10:11 AM, Javier Mart=EDn Rueda wrote: > Just a word of caution: I used to do this in some different machines =20= > (taking periodic snapshots and leaving a few around), and after a =20 > few days or weeks the system would lock up. Any process accessing =20 > the filesystem would block in "ufs" or something like that. After =20 > rebooting, fsck would report fatal errors and I had to do fsck -y in =20= > order to fix them with plenty of scary messages about truncated =20 > inodes, unexpected inconsistencies, and so on. This happened in =20 > several 6.x releases, on different machines, and both under i386 or =20= > amd64. Eventually, I gave up. > > I strongly suggest you try taking hourly snapshots in a non-=20 > production system first for a few weeks, and see if you experience =20 > this kind of problems. Sorry to be a party-pooper. > > It looks as if keeping more than one snapshot eventually is =20 > problematic. Taking single snapshots for dump has never been a =20 > problem, though. > We definitely saw this problem in 6.x. Any reboot after a snapshot =20 would be a mess of fsck fun for a few hours, usually resulting in us =20 losing stuff. But, 7.0 has cured that for me. So far hourly/daily snapshots on any of the 7.0 boxes we've tried it =20 on has worked, it's just so slow it's unusable. I'd like to think =20 it's just being slow because it's being very careful. :) -- Kevin
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