Date: Thu, 11 Jan 2007 11:25:34 -0800 From: Scott Oertel <freebsd@scottevil.com> To: Kris Kennaway <kris@obsecurity.org> Cc: Willem Jan Withagen <wjw@digiware.nl>, freebsd-stable@freebsd.org Subject: Re: running mksnap_ffs Message-ID: <45A68F2E.6040205@scottevil.com> In-Reply-To: <20070111153651.GC31382@xor.obsecurity.org> References: <459ABB40.7050603@digiware.nl> <20070111153651.GC31382@xor.obsecurity.org>
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Kris Kennaway wrote: > On Tue, Jan 02, 2007 at 09:06:24PM +0100, Willem Jan Withagen wrote: > >> Hi, >> >> I got the following Filesystem: >> Filesystem Size Used Avail Capacity iused ifree %iused >> /dev/da0a 1.3T 422G 823G 34% 565952 182833470 0% >> >> Running of a 3ware 9550, on a dual core Opteron 242 with 1Gb. >> The system is used as SMB/NFS server for my other systems here. >> >> I would like to make weekly snapshots, but manually running mksnap_ffs >> freezes access to the disk (I sort of expected that) but the process >> never terminates. So I let is sit overnight, but looking a gstat did not >> reveil any activity what so ever... >> The disk was not released, mksnap_ffs could not be terminated. >> And things resulted in me rebooting the system. >> >> So: >> - How long should I expect making a snapshot to take: >> 5, 15, 30min, 1, 2 hour or even more??? >> > > Yes :) Snapshots were not designed for use in this way (they were > designed to support background fsck and allow faster system recovery > after power failure), so they don't scale as well as you might like on > large filesystems. > > Kris > If snapshots were designed to support background fsck, then why did they not make it more scalable? If you can't create a snapshot without the system locking up, that means fsck won't be able to either, making background fsck worthless for systems with large storage.
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