On 18/06/12 12:08, Avi Miller wrote:
This shouldn't happen in 3.4 or higher - but you're right that btrfs really doesn't like having it's devices disappear.
Yup. Also be warned that if you overfill your filesystem you may find you cannot delete any files as btrfs will be wanting to do COW the metadata first and fail. Two possible work arounds: 1) echo > /btrfs/very-large-file.iso 2) Remount with nodatacow. Also note that one nasty regression has been reported against 3.4 over 3.2, it can massively increase its metadata usage - the reported example showed a filesystem exploding from 10GB of metadata to 84GB but with only about 6GB actually used. It's been bisected to cf1d72c9ceec391d34c48724da57282e97f01122, and apparently a btrfs balance can bring it back down again, but I don't believe it's been fixed yet. It's for very good reason btrfs is described as: Btrfs is highly experimental, and THE DISK FORMAT IS NOT YET FINALIZED. You should say N here unless you are interested in testing Btrfs with non-critical data. cheers, Chris -- Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC