The ZFS ARC is a subject if automatic scaling in any system using ZFS. ARC limiting is only a workaround; the behavior you’re experiencing was pretty much usual for FreeBSD older than 11.x (however, I personally haven’t seen any crashes -only ineffective memory usage); after 11.0 release this behavior was massively mitigated (thus, if you’re using 10.x or ...
Rate Per Second=RPS - Suggestions to consider for your my.cnf [mysqld] section
innodb_io_capacity=1800 # from 200 to allow higher IOPS
read_rnd_buffer_size=256K # from 4M to reduce handler_read_rnd_next RPS of 2560
query_cache_size=0 # from 1M to conserve RAM and QC is OFF already
innodb_lru_scan_depth=100 # from 1024 to conserve CPU cycles every SECOND
8 GB of RAM
Uptime = 14d 21:34:59
You are not running on Windows.
Running 64-bit version
You appear to be running entirely (or mostly) InnoDB.
The More Important Issues:
Alas, nothing jumped out as the answer to your swapping problem. Anyway, here's my comments:
Set long_query_time=1 and turn on the slowlog....
ezjail covers the use-case you described. To answer your question:
How you deal with rolling upgrades?
Let me quote from FreeBSD Handbook 14.6.2. Initial Setup:
To Populate the Jail with installworld The basejail can be installed from binaries created by buildworld on the host with ezjail-admin update ... installworld is executed, installing the host'...
Both of the comments to your post are on the right track. Here is a more fully fledged response.
(TL;DR at bottom)
As root, start by making a safety copy of your /etc/mail directory:
# cd /etc
# cp -Rp mail mail.safety
For the purposes of this example, I'm going to assume that you have no customizations to your email configuration, and in fact, we'll ...