Git at large companies

https://news.ycombinator.com/item?id=3548824

That mentions Amazon, which has embraced git without prohibiting other VCSs. That helped us to solve several problems with scale (100k small repos vs. 3 large repos). I can't comment much, but I can re-post what was said:

Amazon uses Perforce at the moment, and for the most part developers are unhappy with it, as well as the team that has to support it (single giant server prone to outages which block up a couple thousand developers, etc). We're in the process of moving to Git for all of our source.

On the other hand, what you're describing as a problem (what Facebook is describing as going to be a problem) is less likely to be one for Amazon as, with some exceptions that are in the process of fixing the issue, the majority of software at Amazon is developed as a service. Services are segregated into their own package, with most services being broken up into cohesive subpackages (a service my team is building will probably have ~10-13 packages when done), and we have a dependency modeling system for packages baked into everything, from build through deploy, which eliminates most of the cognitive overhead of breaking our services up this way.

All of this translates very well into different Git repositories. What we lose is cohesive atomic commits across packages, which we do get with Perforce. The upshot is we have a team developing a system to handle that specific case.

There you go. SOA (Service Oriented Architecture) solves the repo problem along with a bunch of others.

The problems I've had with git at Amazon are minor, and we do have a very large code-base.