On Tue, 22 Dec 2009 16:51:08 +0200, Alan McKinnon <alan.mckin...@gmail.com> wrote: > On Tuesday 22 December 2009 16:21:08 Christian Könitzer wrote: >> a question to b): >> Can you tell me a fs that supports snappshots (I'm planing to set up a >> new server so you can choose a new fs... (now I am using reiserfs)) and >> maybe how to use it (link)? So if you say "or LSM" does this mean I can >> achieve this also woth LVM? How? >> thx... > > None of the traditional filesystems (ext2|3, reiser) support snapshots. > ZFS< > Btrfs do, possibly ext4 also (the last is a hunch only).
That's basically true. However btrfs is quite experimental still, and I have no serious experience with ZFS, it kind of turns me back the fact that it's a FUSE based fs, though it's certainly possible to use it even for a root system provided that your kernel can load the module at bootup (initrd), I have no idea if there's any downside. I don't have either any notice about snapshotting in ext4 (I remember the plan being discussed but I don't think it has been finally implemented, I'd like to be wrong on this one though). > LVM snapshots a volume, not the filesystem on it. So it tracks extents > that > have changed, not individual files. For backup purposes though, volume and > fs > snapshots are equivalent. > > Snapshots with LVM are easy as pie: > > - create a new volume which is a snapshot of an existing one > - mount the snapshot somewhere > - copy,backup,etc as you like. The volume is read-only so you can't break > it > - umount snapshot > - destroy snapshot > > The LVM man pages contain a wealth of data, as does Google and the LVM > documentation at redhat.com Yep, just googling for something along the lines of "lvm snapshot backup" should give you enough info to start researching. However, for this to be a possibility you first need to convert your system to use lvm. -- Jesús Guerrero
