Can anyone comment on the details of the back-end hw/sw used to run HN? Also will be quite interesting to read a post on any issues/outages and how it was fixed

Can anyone comment on the details of the back-end hw/sw used to run HN? Also will be quite interesting to read a post on any issues/outages and how it was fixed... (though i cannot recall HN being down or slow for as long as i can remember)