Give `+sbwt none` a try and measure how it affects your cluster. It
might reduce the idle CPU usage a bit. The only adverse effect it
might have is it might increase the latency of requests, but it's
something you can measure.
The `+S ${SCHEDULERS}` is how you'd explicitly specify how many
scheduler threads to start, as you've read in the guide, it's mostly
when running in a containerized environment where the containers
"sees" all the CPUs and would start a scheduler for each one of them
even though its quota might effectively be only 1 CPUs.
There is also some background stats gathering and expiring of open
indices and db handles. Those won't show in active tasks. But without
access to the system or more details it's hard to recommend changing
any of them.
> -ssl session_lifetime 300
Don't think that would have a large effect, especially if you
terminate the SSL in haproxy.
Cheers,
-Nick