Я изменил расположение баз /etc/mysql/mysql.conf.d/mysqld.cnf # * Basic Settings # user

= mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /mnt/store/db/mysql/var_lib/mysql
#datadir = /var/lib/mysql
tmpdir = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking
права на каталоги

drwxr-xr-x 3 root root 4096 Nov 14 11:08 mnt
drwxr-xr-x 6 user user 4096 Nov 13 19:35 store
drwxrwxr-x 4 user user 4096 Dec 2 00:00 db
drwxrwxr-x 3 user user 4096 Dec 2 00:01 mysql
drwxrwxr-x 3 user user 4096 Dec 2 00:03 var_lib
drwx------ 6 mysql mysql 4096 Dec 1 01:28 mysql
это не должно быть причиной, но больше никак не вмешивался в работу
и вот что наблюдаю:

sudo /etc/init.d/mysql start
[....] Starting mysql (via systemctl): mysql.serviceJob for mysql.service failed because the control process exited with error code.
See "systemctl status mysql.service" and "journalctl -xe" for details.
failed!
$ systemctl status mysql.service
mysql.service - MySQL Community Server
Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Thu 2019-12-05 21:40:22 EET; 1min 48s ago
Process: 12481 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/run/mysqld/mysqld.pid (code=exited, s
Process: 12471 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS)

Dec 05 21:40:22 MyHost systemd[1]: mysql.service: Service hold-off time over, scheduling restart.
Dec 05 21:40:22 MyHost systemd[1]: mysql.service: Scheduled restart job, restart counter is at 5.
Dec 05 21:40:22 MyHost systemd[1]: Stopped MySQL Community Server.
Dec 05 21:40:22 MyHost systemd[1]: mysql.service: Start request repeated too quickly.
Dec 05 21:40:22 MyHost systemd[1]: mysql.service: Failed with result 'exit-code'.
Dec 05 21:40:22 MyHost systemd[1]: Failed to start MySQL Community Server.
systemd[1]: mysql.service: Start request repeated too quickly.
systemd[1]: mysql.service: Failed with result 'exit-code'.
systemd[1]: Failed to start MySQL Community Server.
подскажете что делать?

права доступа прописаны на папку?