I tried to push to my own hosted bonobo-git server, and did not realise, that the http.postbuffer meant the project directory ...
so just for other confused ones:
why? In my case, I had large zip files with assets and some PSDs pushed as well - to big for the buffer I guess.
How to do this http.postbuffer: execute that command within your project src directory, next to the .git folder, not on the server.
be aware, large temp (chunk) files will be created of that buffer size.
Note: Just check your largest files, then set the buffer.