Date: Mon, 7 Nov 2005 00:09:15 -0500 (EST) From: user <user@dhp.com> To: Eric Anderson <anderson@centtech.com> Cc: freebsd-fs@freebsd.org Subject: Re: UFS2 snapshots on large filesystems Message-ID: <Pine.LNX.4.21.0511070002410.8180-100000@shell.dhp.com> In-Reply-To: <436EB1EC.7010801@centtech.com>
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Eric, Thanks a bunch for your comments. See below: On Sun, 6 Nov 2005, Eric Anderson wrote: > I have several 2TB filesystems, which I do snapshots on. I can report > that it indeed takes a long time to run, but works nevertheless. One > thing to keep in mind though - fsck'ing a 2TB filesystem can take 2GB of > memory (depends on how many files you have, and a few other factors). I > have 4GB of memory in this box, and what I've seen so far is between > 1.5GB and 2.5GB of memory required for fsck to run smoothly on a single > partition. You definitely also want to turn off background fsck, unless > you have extreme amounts of time on your hands. An fsck of a 70% full > 2TB filesystem with a ton of files on it takes many hours, so I often > mount the filesystems unclean (FreeBSD lets me do this) with rw, and > continue my work until I can unmount, fsck, and remount the fs. Can you elaborate ? Namely, how long on the 2GB filesystems ? As far as the fsck is concerned, this only happens on an ungraceful reboot, right ? Assuming a snapshot on a 2GB FS, and assuming no crashes, no long-wait processes like fsck will ever occur, right ? Any other comments ? Do you experience instability/crashes often on systems of this nature ? Again, thanks.
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