Using OpenBSD as local Rsync mirror

[bjd]

I have a handful of Gentoo boxes and want to set up a local Rsync mirror for the Portage tree. Thing is, I want to use my OpenBSD3.7 box as the mirror, it already acts as a file and time server, and want to give it something more interesting to do of an evening.

A glance at the wiki article suggests its just a case of setting up Rsync on OpenBSD and storing the tree somewhere suitable. Then a shell script can point it to a suitable Gentoo mirror and do the sync. Pretty straightforward.

Thing is, I don't want to stop there I was reading the SquashFS for Portage thread and liked what was going on. Saving ~500Mb of space would be useful on a couple of my boxes What I want is the OpenBSD box to take the portage tree its just Rsync'ed and create a SquashFS file, which it can then share out to the Gentoo machines.

The thing I'm not sure about, is that when you emerge --sync, it doesn't just sync the tree, it goes on to build the portage cache. Thats a step that the OpenBSD box would omit, which would mean its missing from the SquashFS file. Thats me assuming whatever the cache builds resides in /usr/portage. I don't quite know what that step does, or if it can be omitted safely. I assume its building a file somewhere for dependency checks and the like. I have been looking at the emerge code to see if I could implement this step on the OpenBSD box in a shell script or similar, but Im not familiar with Python so its hard going

The SquashFS step isn't essential at the end of the day, but it would be nice to get it working, so thought Id ask here to see if it made any sense!
TIA

[slycordinator]

I may be wrong but I think the cache isn't stored inside /usr/portage

edit:
So I was wrong.