> 3a) FFS2 was written to address large file and file system issues.
>     It has background fsck's (via snapshotting).  This is good.

note that background fscking and snapshots are mostly independent of ufs2.  
you can bgfsck ufs1, and also support ufs2 without snapshots.

even so, there are other constraints.  when the size of your file system, 
and especially its number of files, grows too large, 32bit platforms will 
not have enough address space to run fsck with its current algorithm.

-- 
desire is not an occupation