1) One of the most popular question from HBase users has got to be "I have scheduled major compactions to run once per week, why are there so many".
We need to somehow tell the user, wherever we log that there is a "major" compaction, whether it's a major compaction because that's what was in the request (from regular major compaction or user request), or was it just promoted because it took all files. Esp. the latter should be clear.
2) small vs large compaction threads and minor vs major compactions is confusing. Maybe the threads can be named short and long compactions.