Am Sun, 11 May 2014 23:24:34 +0200 schrieb "Stefan G. Weichinger" <li...@xunil.at>:
[...] > ... but it is really nice-to-have the option to snapshot your root-fs, > do-something-to-it (emerge unstable stuff, delete the wrong files, you > name it ...), and if you don't like it you simply boot using your > snapshot ... that is actually really helpful and also rather easy once > you get your head wrapped around the concepts and the few steps > necessary (and it's quick: the snapshot is done in a blink ...) In a presentation by Donny Berkholz at Fosdem this year [0], he mentioned the distro CoreOS, and that they can do atomic updates. I haven't looked it up in detail, but they're website says that they use a dual-root scheme where the update is performed in a second root, which is made the real root after rebooting or after a kexec [1]. It seems to me that this could be made simpler and easier with btrfs snapshots. > As far as I researched btrfs seems to be quite reliable in a not too > complex (read: multi devices) setup ... and backups never hurt anyway. Of course, for me one of *the* big features was the capability to automatically fix corrupted data (the self-healing features of btrfs). This is only possible when you have redundancy across multiple devices. (I'm running a scrub right now.) But even with a single device, you can at least *detect* corruption, I just want to also be able to have it automatically *corrected*. > As I do backups all the time I feel quite confident to test my setups > for the next few days and maybe even completely overhaul my desktop setup. Ditto :) . As risky as it is, this was also a "test" of my backup, in the sense that, while I knew the backups looked okay by manual inspection, I hadn't actually restored from backup yet. Obviously, it worked :) . > -> 2x 1TB HDDs plus 1x 256GB SSD (plus the one older 80GB SSD for tests > right now) ... with LVM and stuff (remember my hassles last week with > the LVMs not activated??) ... I could run one btrfs-pool on the 2 HDDs > and one on the SSD and cut all of my various filesystems out of that. > > Would mixing hdds and the ssd into one pool make sense? I think, no ... ? I suspect something like bcache would work (except I remember reading that btrfs does not work with it yet). > -- > > I will also test running VMs on btrfs-subvolumes and doing snapshots: > > snapshot the underlying subvolume, apply some changes within the VM and > then rollback to the snapshot. > > This would remove LVM-snapshotting out of the way ... etc etc > > As mentioned before, looking forward ... and curious! I'm glad I motivated some people to try btrfs themselves :) . [0] https://www.youtube.com/watch?v=egjcVGKwnrw [1] http://coreos.com/using-coreos/updates/ (section "technical details") -- Marc Joliet -- "People who think they know everything really annoy those of us who know we don't" - Bjarne Stroustrup
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