Earlier quoted context omitted.
We had a repository that grew to about 1.5 gig on github recently (due to hundreds of copies of SWF binaries)... I'm guessing that you have a fairly large average file size here, so your 1.5GB Git repository contains far fewer files than FreeBSD's 1.8GB CVS repository. That said, the strongest evidence that Git can't handle a project the size of FreeBSD comes from Linus himself in a discussion last year about KDE: '"…
That sounds reasonable, even to a Subversion-hater like me. That said, I just took a quick look at the web-based CVS browser for the FreeBSD source repository, and I wonder if splitting the project up into a few smaller should have been considered more carefully? For example, ports go into one repository, the kernel goes in another, documentation into a third, and so on. I'm not a FreeBSD guy, so it's easy for me to…
In fact, that's almost what FreeBSD has done for years. Until recently, there were separate src, ports, doc, www, and projects CVS repositories; the only change now is that the src repository is SVN -- the others are still CVS. As for why the kernel isn't a separate repository: FreeBSD, unlike linux, considers the kernel to be an integral part of a larger whole -- not a completely separate entity. We find that developing the kernel alongside userland utilities and libraries is a very Good Thing.
CVSup and the related toolchain will probably need substantial changes to support anything which isn't CVS anyway.
Nope. All the commits to SVN-src are being replicated to CVS-src (and will be for years to come) -- SVN is basically being used as a new way of doing CVS commits.