So I would like to cautiously throw my results into the round that the mysql tuning options on my server Rocky Linux 9.4 - aarch64) do not lead to the desired success. The mails still arrive every 10 minutes late (see midb.cfg)
I have created the following entry:
/etc/my.cnf.d/grommunio.cnf
[mariadb]
innodb_buffer_pool_size=1G
max_allowed_packet=256M
net_read_timeout=3600
net_write_timeout=3600
read_rnd_buffer_size=8M
skip_name_resolve=ON
sort_buffer_size=8M
table_cache=1000
thread_cache_size=512 #this value is not adopted from the configuration file in my case, I then set it myself in mariadb to be able to test it
wait_timeout=288000
The settings in /etc/gromox/midb.cfg
midb_cache_interval=5minutes
midb_reload_interval=10minutes
are still in place.
On a positive note, the mysql [Warning]s have actually disappeared.
(sorry for writing in German in the first place ...)