MYSQL starts only with innodb_force_recovery. How to repair the database access?

Debian 9 - ISPConfig3 - MYSQL - Postfix - Phpmyadmin error

I please TILL BREHM, the Super Moderator, and anyone who knows any possible solution to help me to cope with a problem.
I've got unexpectedly MYSQL not working. In a while I've found out #mysqld innodb_force_recovery=4, which started my web server, but I can't login into neither ISPConfig3 nor Wordpress panel for my sites nor Roundcube because after fullfilling login forms I'm being thrown back to the same forms nor Phpmyadmin which is not found. I've read hundreds of articles according to my understanding of this MYSQL status, I've done so much tests and careful corrections in configuration with no satisfaction. I have to care for all the data on my server and keep it safe, as the site is devoted for SEO. What is the direction to think of: 1) corrupted databases? OR 2) bad configuration? I'm lost. Any help will be highly appreciated.
My currently in work links:

• http nakamuta.ddns.net port 80
• http nakamuta.ddns.net/webmail port 80
  and login forms:
• https nakamuta.ddns.net port 8080
• https nakamuta.ddns.net port 8081 (not found)

​

Current logs are as follows:
root@nakamuta:/var/log# uname -a

root@nakamuta:/var/log# mysql -V

root@nakamuta:/var/lib/mysql# service mysql status

root@nakamuta:/var/log# tail syslog

root@nakamuta:/var/log/mysql# tail error.log

root@nakamuta:/var/log# df -h

root@nakamuta:/var/log# free -h

root@nakamuta:/var/log# mysql -u root -p

root@nakamuta:/var/log# service postfix status

Thanks in advance! Danke sehr! Спасибо!

 

You should have posted on ISPConfig 3 forum, since you seem to be running ISPConfig on that host.
Start with this, so basic things are checked and shown: https://www.howtoforge.com/community/threads/please-read-before-posting.58408/

Is this a recently installed system? What happened before mysql stopped working?
You could try Internet Search Engines with the error messages in logs:

Code:

Unknown/unsupported storage engine: InnoDB

Your posts become more readable if you:

• put LANG=C before commands that produde non-english text, like LANG=C df -h
• paste the output in CODE tags instead of QUOTE.

See how much better this is:

Code:

$ free -h
              total        used        free      shared  buff/cache   available
Mem:          7,7Gi       5,8Gi       556Mi       883Mi       1,3Gi       757Mi
Swap:            0B          0B          0B

I would also try starting mysql on the command line, that way error messages are shown immediately:

Code:

systemctl stop mysql
systemctl start mysql

Usual things to do when database does not work:

• check databases, they may be broken. PHPMyadmin is easy way to do this
• has configuration in /etc/mysql been changed?
• can the database storage directory/disk be written to?
• is disk full? (you checked this)
• is memory full (you checked this)
• read the docs
• Use Internet Search Engines with error messages