Need urgent help .mariadb not starting

[root@* ~]# systemctl status mariadb.service
● mariadb.service - MariaDB database server
Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Thu 2021-06-10 10:24:51 UTC; 2min 33s ago
Process: 8896 ExecStartPost=/usr/libexec/mariadb-wait-ready $MAINPID (code=exited, status=1/FAILURE)
Process: 8894 ExecStart=/usr/bin/mysqld_safe --basedir=/usr (code=exited, status=0/SUCCESS)
Process: 8859 ExecStartPre=/usr/libexec/mariadb-prepare-db-dir %n (code=exited, status=0/SUCCESS)
Main PID: 8894 (code=exited, status=0/SUCCESS)

Jun 10 10:24:50* systemd[1]: Starting MariaDB database server…
Jun 10 10:24:50 *mariadb-prepare-db-dir[8859]: Database MariaDB is probably initialized in /var/lib/mysql already, nothing is done.
Jun 10 10:24:50 * mariadb-prepare-db-dir[8859]: If this is not the case, make sure the /var/lib/mysql is empty before running mariadb-prepare-db-dir.
Jun 10 10:24:51 * mysqld_safe[8894]: 210610 10:24:51 mysqld_safe Logging to ‘/var/log/mariadb/mariadb.log’.
Jun 10 10:24:51 * mysqld_safe[8894]: 210610 10:24:51 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
Jun 10 10:24:51 * systemd[1]: mariadb.service: control process exited, code=exited status=1
Jun 10 10:24:51 * systemd[1]: Failed to start MariaDB database server.
Jun 10 10:24:51 * systemd[1]: Unit mariadb.service entered failed state.
Jun 10 10:24:51 * systemd[1]: mariadb.service failed.

Check the journal and /var/log/mariadb/mariadb.log to find out why. I can’t guess any more than you can based on the information provided here.

here some copy

210610 8:52:40 [Note] /usr/libexec/mysqld: Shutdown complete

210610 08:52:40 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended
210610 09:35:30 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
210610 9:35:30 InnoDB: The InnoDB memory heap is disabled
210610 9:35:30 InnoDB: Mutexes and rw_locks use GCC atomic builtins
210610 9:35:30 InnoDB: Compressed tables use zlib 1.2.7
210610 9:35:30 InnoDB: Using Linux native AIO
210610 9:35:30 [Note] /usr/libexec/mysqld (mysqld 5.5.68-MariaDB) starting as process 1438 …
210610 9:35:30 InnoDB: Initializing buffer pool, size = 128.0M
210610 9:35:30 InnoDB: Completed initialization of buffer pool
InnoDB: Error: checksum mismatch in data file ./ibdata1
210610 9:35:30 InnoDB: Could not open or create data files.
210610 9:35:30 InnoDB: If you tried to add new data files, and it failed here,
210610 9:35:30 InnoDB: you should now edit innodb_data_file_path in my.cnf back
210610 9:35:30 InnoDB: to what it was, and remove the new ibdata files InnoDB created
210610 9:35:30 InnoDB: in this failed attempt. InnoDB only wrote those files full of
210610 9:35:30 InnoDB: zeros, but did not yet use them in any way. But be careful: do not
210610 9:35:30 InnoDB: remove old data files which contain your precious data!
210610 9:35:30 [ERROR] Plugin ‘InnoDB’ init function returned error.
210610 9:35:30 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed.
210610 9:35:30 [Note] Plugin ‘FEEDBACK’ is disabled.
210610 9:35:30 [ERROR] Unknown/unsupported storage engine: InnoDB
210610 9:35:30 [ERROR] Aborting

210610 9:35:30 [Note] /usr/libexec/mysqld: Shutdown complete

210610 09:35:30 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended
210610 10:00:53 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
210610 10:00:53 [Note] /usr/libexec/mysqld (mysqld 5.5.68-MariaDB) starting as process 24157 …
210610 10:00:53 InnoDB: The InnoDB memory heap is disabled
210610 10:00:53 InnoDB: Mutexes and rw_locks use GCC atomic builtins
210610 10:00:53 InnoDB: Compressed tables use zlib 1.2.7
210610 10:00:53 InnoDB: Using Linux native AIO
210610 10:00:53 InnoDB: Initializing buffer pool, size = 128.0M
210610 10:00:53 InnoDB: Completed initialization of buffer pool
InnoDB: Error: checksum mismatch in data file ./ibdata1
210610 10:00:53 InnoDB: Could not open or create data files.
210610 10:00:53 InnoDB: If you tried to add new data files, and it failed here,
210610 10:00:53 InnoDB: you should now edit innodb_data_file_path in my.cnf back
210610 10:00:53 InnoDB: to what it was, and remove the new ibdata files InnoDB created
210610 10:00:53 InnoDB: in this failed attempt. InnoDB only wrote those files full of
210610 10:00:53 InnoDB: zeros, but did not yet use them in any way. But be careful: do not
210610 10:00:53 InnoDB: remove old data files which contain your precious data!
210610 10:00:53 [ERROR] Plugin ‘InnoDB’ init function returned error.
210610 10:00:53 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed.
210610 10:00:53 [Note] Plugin ‘FEEDBACK’ is disabled.
210610 10:00:53 [ERROR] Unknown/unsupported storage engine: InnoDB
210610 10:00:53 [ERROR] Aborting

210610 10:00:53 [Note] /usr/libexec/mysqld: Shutdown complete

210610 10:00:54 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended
210610 10:02:20 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
210610 10:02:20 [Note] /usr/libexec/mysqld (mysqld 5.5.68-MariaDB) starting as process 1432 …
210610 10:02:20 InnoDB: The InnoDB memory heap is disabled
210610 10:02:20 InnoDB: Mutexes and rw_locks use GCC atomic builtins
210610 10:02:20 InnoDB: Compressed tables use zlib 1.2.7
210610 10:02:20 InnoDB: Using Linux native AIO
210610 10:02:20 InnoDB: Initializing buffer pool, size = 128.0M
210610 10:02:20 InnoDB: Completed initialization of buffer pool
InnoDB: Error: checksum mismatch in data file ./ibdata1
210610 10:02:20 InnoDB: Could not open or create data files.
210610 10:02:20 InnoDB: If you tried to add new data files, and it failed here,
210610 10:02:20 InnoDB: you should now edit innodb_data_file_path in my.cnf back
210610 10:02:20 InnoDB: to what it was, and remove the new ibdata files InnoDB created
210610 10:02:20 InnoDB: in this failed attempt. InnoDB only wrote those files full of
210610 10:02:20 InnoDB: zeros, but did not yet use them in any way. But be careful: do not
210610 10:02:20 InnoDB: remove old data files which contain your precious data!
210610 10:02:20 [ERROR] Plugin ‘InnoDB’ init function returned error.
210610 10:02:20 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed.
210610 10:02:20 [Note] Plugin ‘FEEDBACK’ is disabled.
210610 10:02:20 [ERROR] Unknown/unsupported storage engine: InnoDB
210610 10:02:20 [ERROR] Aborting

210610 10:02:20 [Note] /usr/libexec/mysqld: Shutdown complete

210610 10:02:20 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended
210610 10:03:57 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
210610 10:03:57 [Note] /usr/libexec/mysqld (mysqld 5.5.68-MariaDB) starting as process 7033 …
210610 10:03:57 InnoDB: The InnoDB memory heap is disabled
210610 10:03:57 InnoDB: Mutexes and rw_locks use GCC atomic builtins
210610 10:03:57 InnoDB: Compressed tables use zlib 1.2.7
210610 10:03:57 InnoDB: Using Linux native AIO
210610 10:03:57 InnoDB: Initializing buffer pool, size = 128.0M
210610 10:03:57 InnoDB: Completed initialization of buffer pool
InnoDB: Error: checksum mismatch in data file ./ibdata1
210610 10:03:57 InnoDB: Could not open or create data files.
210610 10:03:57 InnoDB: If you tried to add new data files, and it failed here,
210610 10:03:57 InnoDB: you should now edit innodb_data_file_path in my.cnf back
210610 10:03:57 InnoDB: to what it was, and remove the new ibdata files InnoDB created
210610 10:03:57 InnoDB: in this failed attempt. InnoDB only wrote those files full of
210610 10:03:57 InnoDB: zeros, but did not yet use them in any way. But be careful: do not
210610 10:03:57 InnoDB: remove old data files which contain your precious data!
210610 10:03:57 [ERROR] Plugin ‘InnoDB’ init function returned error.
210610 10:03:57 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed.
210610 10:03:57 [Note] Plugin ‘FEEDBACK’ is disabled.
210610 10:03:57 [ERROR] Unknown/unsupported storage engine: InnoDB
210610 10:03:57 [ERROR] Aborting

210610 10:03:57 [Note] /usr/libexec/mysqld: Shutdown complete

210610 10:03:57 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended
210610 10:09:32 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
210610 10:09:32 [Note] /usr/libexec/mysqld (mysqld 5.5.68-MariaDB) starting as process 25964 …
210610 10:09:32 InnoDB: The InnoDB memory heap is disabled
210610 10:09:32 InnoDB: Mutexes and rw_locks use GCC atomic builtins
210610 10:09:32 InnoDB: Compressed tables use zlib 1.2.7
210610 10:09:32 InnoDB: Using Linux native AIO
210610 10:09:32 InnoDB: Initializing buffer pool, size = 128.0M
210610 10:09:32 InnoDB: Completed initialization of buffer pool
InnoDB: Error: checksum mismatch in data file ./ibdata1
210610 10:09:32 InnoDB: Could not open or create data files.
210610 10:09:32 InnoDB: If you tried to add new data files, and it failed here,
210610 10:09:32 InnoDB: you should now edit innodb_data_file_path in my.cnf back
210610 10:09:32 InnoDB: to what it was, and remove the new ibdata files InnoDB created
210610 10:09:32 InnoDB: in this failed attempt. InnoDB only wrote those files full of
210610 10:09:32 InnoDB: zeros, but did not yet use them in any way. But be careful: do not
210610 10:09:32 InnoDB: remove old data files which contain your precious data!
210610 10:09:32 [ERROR] Plugin ‘InnoDB’ init function returned error.
210610 10:09:32 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed.
210610 10:09:32 [Note] Plugin ‘FEEDBACK’ is disabled.
210610 10:09:32 [ERROR] Unknown/unsupported storage engine: InnoDB
210610 10:09:32 [ERROR] Aborting

210610 10:09:32 [Note] /usr/libexec/mysqld: Shutdown complete

210610 10:09:32 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended
210610 10:16:41 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
210610 10:16:41 [Note] /usr/libexec/mysqld (mysqld 5.5.68-MariaDB) starting as process 3674 …
210610 10:16:41 InnoDB: The InnoDB memory heap is disabled
210610 10:16:41 InnoDB: Mutexes and rw_locks use GCC atomic builtins
210610 10:16:41 InnoDB: Compressed tables use zlib 1.2.7
210610 10:16:41 InnoDB: Using Linux native AIO
210610 10:16:41 InnoDB: Initializing buffer pool, size = 128.0M
210610 10:16:41 InnoDB: Completed initialization of buffer pool
InnoDB: Error: checksum mismatch in data file ./ibdata1
210610 10:16:41 InnoDB: Could not open or create data files.
210610 10:16:41 InnoDB: If you tried to add new data files, and it failed here,
210610 10:16:41 InnoDB: you should now edit innodb_data_file_path in my.cnf back
210610 10:16:41 InnoDB: to what it was, and remove the new ibdata files InnoDB created
210610 10:16:41 InnoDB: in this failed attempt. InnoDB only wrote those files full of
210610 10:16:41 InnoDB: zeros, but did not yet use them in any way. But be careful: do not
210610 10:16:41 InnoDB: remove old data files which contain your precious data!
210610 10:16:41 [ERROR] Plugin ‘InnoDB’ init function returned error.
210610 10:16:41 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed.
210610 10:16:41 [Note] Plugin ‘FEEDBACK’ is disabled.
210610 10:16:41 [ERROR] Unknown/unsupported storage engine: InnoDB
210610 10:16:41 [ERROR] Aborting

210610 10:16:41 [Note] /usr/libexec/mysqld: Shutdown complete

210610 10:16:41 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended
210610 10:21:02 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
210610 10:21:02 [Note] /usr/libexec/mysqld (mysqld 5.5.68-MariaDB) starting as process 1437 …
210610 10:21:02 InnoDB: The InnoDB memory heap is disabled
210610 10:21:02 InnoDB: Mutexes and rw_locks use GCC atomic builtins
210610 10:21:02 InnoDB: Compressed tables use zlib 1.2.7
210610 10:21:02 InnoDB: Using Linux native AIO
210610 10:21:02 InnoDB: Initializing buffer pool, size = 128.0M
210610 10:21:02 InnoDB: Completed initialization of buffer pool
InnoDB: Error: checksum mismatch in data file ./ibdata1
210610 10:21:02 InnoDB: Could not open or create data files.
210610 10:21:02 InnoDB: If you tried to add new data files, and it failed here,
210610 10:21:02 InnoDB: you should now edit innodb_data_file_path in my.cnf back
210610 10:21:02 InnoDB: to what it was, and remove the new ibdata files InnoDB created
210610 10:21:02 InnoDB: in this failed attempt. InnoDB only wrote those files full of
210610 10:21:02 InnoDB: zeros, but did not yet use them in any way. But be careful: do not
210610 10:21:02 InnoDB: remove old data files which contain your precious data!
210610 10:21:02 [ERROR] Plugin ‘InnoDB’ init function returned error.
210610 10:21:02 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed.
210610 10:21:02 [Note] Plugin ‘FEEDBACK’ is disabled.
210610 10:21:02 [ERROR] Unknown/unsupported storage engine: InnoDB
210610 10:21:02 [ERROR] Aborting

210610 10:21:02 [Note] /usr/libexec/mysqld: Shutdown complete

210610 10:21:02 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended
210610 10:32:04 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
210610 10:32:04 [Note] /usr/libexec/mysqld (mysqld 5.5.68-MariaDB) starting as process 31141 …
210610 10:32:04 InnoDB: The InnoDB memory heap is disabled
210610 10:32:04 InnoDB: Mutexes and rw_locks use GCC atomic builtins
210610 10:32:04 InnoDB: Compressed tables use zlib 1.2.7
210610 10:32:04 InnoDB: Using Linux native AIO
210610 10:32:04 InnoDB: Initializing buffer pool, size = 128.0M
210610 10:32:04 InnoDB: Completed initialization of buffer pool
InnoDB: Error: checksum mismatch in data file ./ibdata1
210610 10:32:04 InnoDB: Could not open or create data files.
210610 10:32:04 InnoDB: If you tried to add new data files, and it failed here,
210610 10:32:04 InnoDB: you should now edit innodb_data_file_path in my.cnf back
210610 10:32:04 InnoDB: to what it was, and remove the new ibdata files InnoDB created
210610 10:32:04 InnoDB: in this failed attempt. InnoDB only wrote those files full of
210610 10:32:04 InnoDB: zeros, but did not yet use them in any way. But be careful: do not
210610 10:32:04 InnoDB: remove old data files which contain your precious data!
210610 10:32:04 [ERROR] Plugin ‘InnoDB’ init function returned error.
210610 10:32:04 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed.
210610 10:32:04 [Note] Plugin ‘FEEDBACK’ is disabled.
210610 10:32:04 [ERROR] Unknown/unsupported storage engine: InnoDB
210610 10:32:04 [ERROR] Aborting

210610 10:32:04 [Note] /usr/libexec/mysqld: Shutdown complete

210610 10:32:04 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended

What OS/version?

This looks like the database was created with MySQL and then switched to mariadb.

i have fixed this issue it was ibdata1 issue