Hadoop Code - Git and SVN

All the Apache Hadoop Code is hosted in SVN. How does Git help in Had开发者_如何学运维oop development process? It's not clear from the below article.

http://wiki.apache.org/hadoop/GitAndHadoop

The official location for Hadoop is the Apache SVN repository; Git is also supported, and useful if you want to make lots of local changes -and keep those changes under some form or private or public revision control.

http://wiki.apache.org/hadoop/HowToContribute

Update: the official location is now the Apache Git repository.

A lot of people use Git with Hadoop because they have their own patches to make to Hadoop, and Git helps them manage it. Apache serves up read-only Git versions of their source at http://git.apache.org/. People cannot commit changes with Git; for that the patches need to be applied to the SVN repositories.

http://wiki.apache.org/hadoop/HowToContribute

These lines make it pretty clear.