On Mar 13, 2014, at 7:14 PM, Lists <li...@benjamindsmith.com> wrote: > > I'm assuming that BTRFS send/receive works similar to ZFS's similarly named > feature.
Similar yes but not all options are the same between them. e.g. zfs send -R replicates all descendent file systems. I don't think zfs requires volumes, filesystems, or snapshots to be read-only, whereas btrfs send only works on read only snapshot-subvolumes. There has been some suggestion of a recursive snapshot creation and recursive send for btrfs. > So just I don't get the "backup" problem. Place btrfs' equivalent of a pool > on the external drive, and use send/receive of the filesystem or snapshot(s). > Does BTRFS work so differently in this regard? If so, I'd like to know what's > different. Top most thing in zfs is the pool, which on btrfs is the volume. Neither zfs send or btrfs send works on this level to send everything within a pool/volume. zfs has the file system and btrfs has the subvolume which can be snapshot. Either (or both) can be used with send. zfs also has the volume which is a block device that can be snapshot, there isn't yet a btrfs equivalent. Btrfs and zfs have clones but the distinction is stronger with zfs. Like zfs snapshots can't be deleted unless its clones are deleted. Btrfs send has a -c clone-src option that I don't really understand, and also the --reflink which is a clone at the file level. Anyway there are a lot of similarities but also quite a few differences. Basic functionality seems pretty much the same. > > My primary interest in BTRFS vs ZFS is two-fold: > > 1) ZFS has a couple of limitations that I find disappointing, that don't > appear to be present in BTRFS. > A) Inability to upgrade a non-redundant ZFS pool/vdev to raidz or increase > the raidz (redundancy) level after creation. (Yes, you can plan around this, > but I see no good reason to HAVE to) > B) Inability to remove a vdev once added to a pool. > > 2) Licensing: ZFS on Linux is truly great so far in all my testing, can't > throw enough compliments their way, but I would really like to rely on a > "first class citizen" as far as the Linux kernel is concerned. 3. On btrfs you can delete a parent subvolume and the children remain. On zfs, you can't destroy a zfs filesystem/volume unless its snapshots are deleted, and you can't delete snapshots unless their clones are deleted. Chris Murphy -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
