Before all the trolling about Microsoft starts up, does anyone have current information on what these systems are?

In the enterprise space, a 'data storage system' could be an Array or a SAN or a lightpath etc, with usually quite long failover times. For an org like GitHub I'd think more like an object store (an Array-of-Hosts, if you will) or whatever storage mechanism holds their database files. Do they self host this sort of thing or is it an AWS/GCE/Azure service?

FWIW, all git commands are working fine for me (create a branch, push, colleagues can fetch my branch), but the UI doesn't show my branch & nor can I review/comment on PRs.