How to track stable on multiple servers?

[Slawa Olhovchenkov]

I have some set of FreeBSD servers in public internet and continue to
find optimal way for track -stable branch.

Handbook give next metods:

1. Tracking -security branch by freebsd-update.
   I want -stable, -security don't have wanted features.

2. svn & rebuilding world localy. To long and wery badly automated,
   bad version synchronisation between servers.

3. svn & rebuilding world on build server, install localy by NFS.
   Servers in public internet, I am to be  afraid exposing NFS to
   public internet. Also, need to have localy /etc/{make,src}.conf in
   sync with build server. Also badly automated.

4. Build private freebsd-update-server and build (simularity to
   security btanch) updates for -stable.
   Need essentially dedicated server -- during build system time
   changed and this is may be raise side effects.
   freebsd-update work wery long time (hours) and accumulate a lot of
   garbage:

# du -ms /var/db/freebsd-update/
2010    /var/db/freebsd-update/

   freebsd-update-server/freebsd-update too bugly and debuggint is not
   easy.
   config mergering working worse mergemaster.
   Don't allow to repair damaged files (freebsd-update IDS detect
   changes but don't repair this).

5. nanobsd.
   Don't automatic save /etc and etc.
   pkg updated throw system image update and reboot. Unaccpetable.


Something else?