Best Journaling File System - ZFS/???

[Wojciech Puchar]

>>> I use gjournal since FreeBSD 7.0 and it seems to work fine.
>> is it really smart enough to not write everything twice or am i wrong?
>
> It writes everything twice :)
>
> (but every journaling system has to write something twice)

there is a big difference between something (metadata, short data 
writes and everything (like huge file data)