I want to configure a desktop system in which the home filesystem would be redundant (e.g. RAID-1), and would have weekly snapshots taken. I've already done this with ZFS, the snapshot system is wonderful, and with send/recv you can easily create backups on external media. Unfortunately, at that point, I want GNU+Linux and not FreeBSD or Solaris, so I'm looking for suggestions for good alternatives.
I reckon that my alternatives are:
- btrfs - it seems to be exactly what I need, it has snapshots and commands that allow you to easily replicate
zfs send. Yet all documentation mentions that it's still experimental. I can't seem to find any actual reports on its reliability or usability issues. Can you point me to any information on that issue that could clarify whether it would be a possible choice? I have a large preference for this option, mostly because I don't want to reformat the drives when btrfs becomes ready, but I there's no information on whether it's usable at all, whether it's a silly idea to use it, etc. The question that I cannot get the answer to is what does "experimental" mean.
- lvm snapshots and ext4 - preferably not, since it can consume an awful amount of space when new files are created. Creating 200 GB files requres 200 GB free space and 200 GB additionally for snapshots. I also have found it unreliable -- failed metadata rewrite results in an unreadable PV. I'm wondering how btrfs would compare here.
- A single filesystem (ext4) on a RAID-1 array with custom COW snapshots with hardlinks (like
cp -al). That's my current preference if I can't use btrfs.
So how experimental btrfs is, which should I choose, and do I have any other options? What if I don't keep external incremental backups, would that affect my choice?