MariaDB Database set key_buffer_size to 20% of available RAM, MariaDB no longer runs

Webmin
1
SYSTEM INFORMATION
OS type and version AlmaLinux 9.5
Webmin version 2.202

Webmin → Servers → MariaDB Database server
and set key_buffer_size to 20% of available RAM (recommended at MariaDB website for MyISAM)

Now it errors:
“Error! MariaDB is not running on your system - database list could not be retrieved.”
MariaDB error message
The full MariaDB error message was : DBI connect failed : Can’t connect to local server through socket ‘/var/lib/mysql/mysql.sock’ (2) ?

Attempt to start MariaDB: Job for mariadb.service failed because the control process exited with error code.
See “systemctl status mariadb.service” and “journalctl -xeu mariadb.service” for details.

systemctl status mariadb.service:

× mariadb.service - MariaDB 10.5 database server
     Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; preset: disabled)
     Active: failed (Result: exit-code) since Sat 2024-12-28 09:08:41 AEDT; 1min 5s ago
       Docs: man:mariadbd(8)
             https://mariadb.com/kb/en/library/systemd/
    Process: 4953 ExecStartPre=/usr/libexec/mariadb-check-socket (code=exited, status=0/SUCCESS)
    Process: 4975 ExecStartPre=/usr/libexec/mariadb-prepare-db-dir mariadb.service (code=exited, status=0/SUCCESS)
    Process: 5010 ExecStart=/usr/libexec/mariadbd --basedir=/usr $MYSQLD_OPTS $_WSREP_NEW_CLUSTER (code=exited, status=7)
   Main PID: 5010 (code=exited, status=7)
     Status: "MariaDB server is down"
        CPU: 185ms

Dec 28 09:08:41 hostname.example.com.au systemd[1]: Starting MariaDB 10.5 database server...
Dec 28 09:08:41 hostname.example.com.au mariadb-prepare-db-dir[4975]: Database MariaDB is probably initialized in /var/lib/mysql already, nothing is done.
Dec 28 09:08:41 hostname.example.com.au mariadb-prepare-db-dir[4975]: If this is not the case, make sure the /var/lib/mysql is empty before running mariadb-prepare-db-dir.
Dec 28 09:08:41 hostname.example.com.au systemd[1]: mariadb.service: Main process exited, code=exited, status=7/NOTRUNNING
Dec 28 09:08:41 hostname.example.com.au systemd[1]: mariadb.service: Failed with result 'exit-code'.
Dec 28 09:08:41 hostname.example.com.au systemd[1]: Failed to start MariaDB 10.5 database server.

journalctl -xeu mariadb.service:

A start job for unit mariadb.service has begun execution.
 The job identifier is 1019.
Dec 28 09:08:41 hostname.example.com.au mariadb-prepare-db-dir[4975]: Database MariaDB is probably initialized in /var/lib/mysql already, nothing is done.
Dec 28 09:08:41 hostname.example.com.au mariadb-prepare-db-dir[4975]: If this is not the case, make sure the /var/lib/mysql is empty before running mariadb-prepare-db-dir.
Dec 28 09:08:41 hostname.example.com.au systemd[1]: mariadb.service: Main process exited, code=exited, status=7/NOTRUNNING
 Subject: Unit process exited
Defined-By: systemd
Support: https://wiki.almalinux.org/Help-and-Support

An ExecStart= process belonging to unit mariadb.service has exited.

The process' exit code is 'exited' and its exit status is 7.
Dec 28 09:08:41 hostname.example.com.au systemd[1]: mariadb.service: Failed with result 'exit-code'.
Subject: Unit failed
Defined-By: systemd
Support: https://wiki.almalinux.org/Help-and-Support

The unit mariadb.service has entered the 'failed' state with result 'exit-code'.
Dec 28 09:08:41 hostname.example.com.au systemd[1]: Failed to start MariaDB 10.5 database server.
Subject: A start job for unit mariadb.service has failed
Defined-By: systemd 
Support: https://wiki.almalinux.org/Help-and-Support
 A start job for unit mariadb.service has finished with a failure.
 
 The job identifier is 1019 and the job result is failed.

Contents of /var/lib/MySQL:
aria_log.00000001 aria_log_control databasename ib_buffer_pool ib_logfile0 ibdata1 multi-master.info mysql mysql_upgrade_info performance_schema

The error message
“Dec 28 09:08:41 hostname.example.com.au mariadb-prepare-db-dir[4975]: Database MariaDB is probably initialized in /var/lib/mysql already, nothing is done.
Dec 28 09:08:41 hostname.example.com.au mariadb-prepare-db-dir[4975]: If this is not the case, make sure the /var/lib/mysql is empty before running mariadb-prepare-db-dir.”
appears to imply the /var/lib/MySQL directory should be empty?

2

No!

It is implying there’s already data there. If you have already databases, you should want it to find data there. It would be a catastrophic loss if it were empty and your only remedy would be restoring from backup.

3

Thanks, that’s what I thought.

At a loss why a simple config change would cause the server to stop.

4

For me incorrect syntax can break stuff, and it won’t stop the server, it will stop it from restarting as the config file is only read when starting.

5

Well, I would start by undoing that change. Maybe you made a typo and it wasn’t a valid configuration directive?

6

Unfortunately can’t do it via Webmin (unlikely an error in entering a one digit number in the key_buffer_size) :

delete
delete1580×349 44.8 KB

7

Then do it via SSH.

It is bug-like, though, that we need a running Mariadb server to manage the configuration file. @Jamie can you make the Webmin Mariadb/MySQL module allow editing config files even when the server isn’t running and won’t start?

1 Like
8

Thank you.

Commented out the line in /etc/my.cnf.d/mariadb-server.cnf

ie (set via Webmin interface):

set-variable = key_buffer_size=2G

by editing config file manually to

# set-variable = key_buffer_size=2G

and entered

key_buffer_size=2G

Server is back.

Note: the key_buffer_size in the Webmin MariaDB Server Configuration interface still shows radio button for default, not the 2G (bug or accessing incorrect config file?) as

MySQL CLI shows:
SHOW GLOBAL VARIABLES LIKE “key_buffer_size”;
±----------------±-----------+
| Variable_name | Value |
±----------------±-----------+
| key_buffer_size | 2147483648 |
±----------------±-----------+