Some versioned storage program?

[Xin LI]

Hi, folks,

I'm looking for some versioned storage program that can fulfill the 
following requirements:

  - Open source/Free Software that can run on FreeBSD, or not far (i.e. 
on other POSIX OS)
  - Support of atomic commit/rollback.
  - Fast checkin time (At least,  when added/changed files are 
explicitly specified).
  - Fast update time (i.e. something like 'cvsup -s' that makes it 
possible to trust bookkeeping file rather than stat'ing every files)
  - Scalable for a large number of files, directories and revisions. 
Say, it is not acceptable for it to store a zillion of revisions as 
individual files within one directory.
  - Ideally it can support some sort of "hook" functions upon commit so 
that changes can be notified in some way such as e-mail.
  - Ideally it can support fast export of a snapshot for HEAD and 
"nearby" revision like HEAD - 1, etc.

I think what I need is some SCM software like subversion or hg, but I do 
not know if there is some superior stuff that matches these requirements 
better.  Any other suggestions?

Cheers,
-- 
Xin LI <delphij at delphij.net>	http://www.delphij.net/
FreeBSD - The Power to Serve!