Hi all,
I use several months the btrfs filesystem mounted on /opt. The main advantage is that I can quickly copy/remove the /opt/elinos* stuff Most likely it applies also for pikeOS ;) I use current head as example but it will work with anything. Subvolumes looks like a directory.
1) create a btrfs filesystem and mount it on /opt and install btrfs tools
2) create an empty subvolume
btrfs subvolume create /opt/elinos-D5.2
3) install elinos D52 as usual.
4) after installation do the snapshot of fresh install:
btrfs subvolume snapshot /opt/elinos-D5.2 /opt/elinos-D5.2-DXxxxx-whatever-backup
(it will take just a sub-second to create a copy!)
5) repeat step 4 just after you install something good like SR release etc…
6) if you dont like current elinos , you may delete it with:
btrfs subvolume delete /opt/elinos-D5.2
(also deleted in fraction of second, renaming directory will work too in case you need that later)
7) then you can go back to whatever you prepared in step 4)
btrfs subvolume snapshot /opt/elinos-D5.2-DXxxxx-whatever-backup /opt/elinos-D5.2
Advantages, its super fast, snapshots does not take more space (only changed files). I use it on 2.6.33. The only problem is that the disk format of btrfs is not yet freezed so all changes are only forward compatible. So if you update your kernel you cannot go back (valid from 2.6.31+).