Google Piper→

Wired:

Piper spans about 85 terabytes of data (aka 85,000 gigabytes), and Google’s 25,000 engineers make about 45,000 commits (changes) to the repository each day. That’s some serious activity. While the Linux open source operating spans 15 million lines of code across 40,000 software files, Google engineers modify 15 million lines of code across 250,000 files each week.

Piper, not included in that excerpt, is Google’s in-house version control system, which hosts the two billion lines of code that make up the functional Google web services.
It’s an astonishingly huge setup.