On Thursday 13 March 2014 17:29:11 George Mitchell wrote: > I currently use rsync to a separate drive to maintain a > backup copy, but it is not integrated into the array like n-way would > be, and is definitely not a perfect solution. Could you explain how you're using rsync? I was just about to copy a btrfs filesystem to another disk. That filesystem has several subvolumes and about 100 snapshots overall. Owing to COW, this amounts to about 1.2TB. However, I reckon that rsync doesn't know anything about COW and accordingly would blow up my data immensely on the destination disk. How do I copy a btrfs filesystem preserving its complete contents? How do I update such a copy? Yes, I want to keep the subvolume layout of the original and I want to copy all snapshots. I don't think send/receive is the answer, but it's likey I don't understand it well enough. I'm concerned, that a send/receive-based approach is not robust against mishaps. Consider: I want to incrementally back-up a filesystem to two external disks. For this I'd have to for each subvolume keep a snapshot corresponding to its state on the backup disk. If I make any mistake in managing these snapshots, I can't update the external backup anymore. Also, I don't understand whether send/receive would allow me to copy/update a subvolume *including* its snapshots. Things have become a little more complicated than I had hoped for, but I've only been using btrfs for a couple of weeks. Michael -- Michael Schuerig mailto:michael@xxxxxxxxxxx http://www.schuerig.de/michael/ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
