Improvements to fsck performance in -current ...?

[Marc G. Fournier]

On Wed, 1 Oct 2003, Lukas Ertl wrote:

> > are either of these enhancements back-patchable to the 4.x fsck, or do
> > they require some non-4.x compatible changes to work?
>
> It's not just the fsck application itself, background fsck basically needs
> file system snapshots, which are only available on UFS2, and I'm not sure
> if they can be backported to UFS1 at all.

Ah, okay, so when I move my servers to 5.x, then I'm going to need to
reformat the systems from scratch, else I lose some serious improvements
... is there a list somewhere of what UFS2 has over UFS1?  "file system
snapshots", is that similar to journalling?