Joe from GitHub here, we'll talk about it later posts but GLB is based on a number of open source projects including, haproxy, iptables, FoU and pf_ring.
Many existing open source solutions are optimized for short lived HTTP requests and don't address the long running connection issue (like a large git clone). We wanted something better for our use case.
I'm currently working with GitHub Support on dealing with zip downloads of a 5GB repo failing after 2-3 minutes, with curl error "transfer closed with outstanding read data remaining".
Sure about the long running connection issue being solved? :-)
Many existing open source solutions are optimized for short lived HTTP requests and don't address the long running connection issue (like a large git clone). We wanted something better for our use case.