Copying a 1TB disk image on a btrfs partition with
cp takes less than a second on my Ubuntu 14.10 amd64 with Linux 3.16.0. Why does it take at least 5 minutes and requires > 1 GB to be read on a ZFS pool with deduplication turned on and compression turned off?
I just want to improve my understanding of ZFS and figure out whether ZFS is an appropriate alternative as deduplicating filesystem for me (by understanding e.g. whether copy action described for btrfs are possible on ZFS at all (on linux 3.16)).
EDIT: After Stéphane Chazelas' comment I run
cp --reflink=always file file.bk which fails with
$ LANG=C cp --reflink=always file file.bk cp: failed to clone 'image_lvm.img.bk2' from 'image_lvm.img': Inappropriate ioctl for device