Guess what one of the top disk latency inducers is on my (functionally mostly idle) server.
# zfsslower
Tracing ZFS operations slower than 10 ms
TIME COMM PID T BYTES OFF_KB LAT(ms) FILENAME
09:14:10 async_49 2675004 S 0 0 18.29 journal.jif
The mysteriously named async_49 represents Mnesia as used by RabbitMQ as part of… Zulip.
Have I mentioned that a Zulip instance hosting 3 users is a waste of resources? Oh, I have, haven’t I?