Yes, exactly - htop is a curses application that shows instantaneous samples of a few system metrics, but it mostly lists processes - this is nothing like Vector at all...

Grafana, Graphite, StatsD, Skyline.

I think the reason is they have a bunch of ephemeral hosts which they don't want to put in a central web interface or collect statistics on. They are only interested in getting some insight as to what went wrong with this host so they can fix it in the future.

Yes, Atlas, which is also open source: http://techblog.netflix.com/2014/12/introducing-atlas-netfli... . Atlas monitors cloud-wide, and stores historical metrics at a one minute granularity.

Vector is for per-instance custom drilldowns. I gave a talk last year where I showed how they both fit together: http://www.brendangregg.com/blog/2014-09-27/from-clouds-to-r...