Ubuntu Has Plans For Btrfs In 2011, 2012

[oleid]

Hi!

Here is a nice article about ZFS and BtrFS:

http://lwn.net/Articles/342892/

It also includes some historical and technical information.

[Jimbo]

ZFS and BTRFS are based on COW copy-on-write, this permits a series of advanced FS features. If you really want to innovate you have to discover something better than COW. And you need to change what data centers professionals are demanding. It's not easy

This quote is basically valid to BTRFS too.

"ZFS uses a copy-on-write, transactional object model. All block pointers within the filesystem contain a 256-bit checksum of the target block which is verified when the block is read. Blocks containing active data are never overwritten in place; instead, a new block is allocated, modified data is written to it, and then any metadata blocks referencing it are similarly read, reallocated, and written. To reduce the overhead of this process, multiple updates are grouped into transaction groups, and an intent log is used when synchronous write semantics are required.

The ZFS copy-on-write model has another powerful advantage: when ZFS writes new data, instead of releasing the blocks containing the old data, it can instead retain them, creating a snapshot version of the file system. ZFS snapshots are created very quickly, since all the data comprising the snapshot is already stored; they are also space efficient, since any unchanged data is shared among the file system and its snapshots.

Writable snapshots ("clones") can also be created, resulting in two independent file systems that share a set of blocks. As changes are made to any of the clone file systems, new data blocks are created to reflect those changes, but any unchanged blocks continue to be shared, no matter how many clones exist."

[kraftman]

The problem is that ZFS development will not stand still. It is like Wine, which copies WinXP. But meanwhile MS has released Vista, and Win7. And then will release Win8. Wine will never catch up.

This will be true if the development power will be the same

[nanonyme]

ZFS and BTRFS are based on COW copy-on-write, this permits a series of advanced FS features. If you really want to innovate you have to discover something better than COW. And you need to change what data centers professionals are demanding. It's not easy

Actually as far as I've heard, Btrfs is innovative compared to ZFS in that matter. People developing ZFS thought COW on B-trees wasn't practical or even doable, then Btrfs developers did it.