Trying to make a mirror for a disconnected lab

[Duncan Hutty]

I'm planning to build a "lab" of perhaps 15 freebsd machines.

Not only do I want to be a good sysadmin and only download what I need, 
but another issue is that these machines will live on a network that 
will not have a reliable connection to the internet.

Therefore I want to build a mirror of parts of ftp.freebsd.org so that 
the lead machine (for each of 2 architectures) can build packages for 
the other machines to install.

I think that if I mirror:
ports/distfiles
releases/<arch>/<version>-RELEASE

then I think I will be able to install FreeBSD on each machine and build 
packages of anything from ports that I want to install on all the 
machines. And then for each individual machine set PKG_PATH to be the 
nfs served location from the main server.

Therefore to make my mirror, I have a rsync filter file that looks 
something like this:
+ /ports/
+ /ports/distfiles/
+ /ports/distfiles/*

+ /releases/
+ /releases/i386/
+ /releases/i386/7.2-RELEASE/
+ /releases/i386/7.2-RELEASE/*
+ /releases/i386/7.2-RELEASE/base/
+ /releases/i386/7.2-RELEASE/base/*
etc.

- *

Hopefully, someone can give me confidence that this is a reasonable 
plan? Or am I going about this wrongheadedly?

I have a question:

Q. ports/distfiles contains tarballs of multiple versions of each 
software; I assume that I only need one version of each tarball. And 
since this mirror as described comes to ~100GiB, how can I modify my 
rsync filter so I don't get anything more than either the latest tarball 
for each software package in distfiles or whichever version accords to 
the Makefiles provided by ports.tgz

Hopefully some of this detail will be of help to someone else in a 
similar position.
--
Duncan Hutty