On Tue, May 19, 2015 at 6:13 AM, Neil Bothwick <n...@digimed.co.uk> wrote: > On Tue, 19 May 2015 10:02:38 +0100, Peter Humphrey wrote: > >> > skip mdadm and lvm ... and try btrfs as you have the chance on shiny >> > new hardware >> >> I also have a spare external hard disk, which I could experiment with >> for snapshots etc. > > Snapshots are subvolumes in btrfs, so they stay in the same filesystem. > That's why they are so fast. > > It's a similar situation with ZFS.
Yup. In both cases they're copy-on-write, so they don't consume additional space except to the extent that things change. Also, in both cases you can serialize a snapshot (either in its entirety or as a diff vs a previous snapshot) and store it on separate storage. This is mainly done for backup (storing the serialized files) or replication (replaying them onto another server with the same filesystem). But, neither ZFS nor btrfs are without issue on Linux, so I'd use care in a production environment. The btrfs issues tend to revolve around stability, and the zfs issues tend to revolve around dealing with out-of-mainline code and legal/license issues. -- Rich
