The article directories
Error overview solution

Error in

2020-06-29  0:17:42 0 [Note] InnoDB: Check that you do not already have another mysqld process using the same InnoDB data or log files.
2020-06-29  0:17:43 0 [ERROR] InnoDB: Unable to lock ./ibdata1 error: 11
2020-06-29  0:17:43 0 [Note] InnoDB: Check that you do not already have another mysqld process using the same InnoDB data or log files.
2020-06-29  0:17:44 0 [ERROR] InnoDB: Unable to lock ./ibdata1 error: 11
2020-06-29  0:17:44 0 [Note] InnoDB: Check that you do not already have another mysqld process using the same InnoDB data or log files.
2020-06-29  0:17:45 0 [ERROR] InnoDB: Unable to lock ./ibdata1 error: 11
2020-06-29  0:17:45 0 [Note] InnoDB: Check that you do not already have another mysqld process using the same InnoDB data or log files.
2020-06-29  0:17:46 0 [ERROR] InnoDB: Unable to lock ./ibdata1 error: 11
2020-06-29  0:17:46 0 [Note] InnoDB: Check that you do not already have another mysqld process using the same InnoDB data or log files.
2020-06-29  0:17:47 0 [ERROR] InnoDB: Unable to lock ./ibdata1 error: 11
2020-06-29  0:17:47 0 [Note] InnoDB: Check that you do not already have another mysqld process using the same InnoDB data or log files.
2020-06-29  0:17:48 0 [ERROR] InnoDB: Unable to lock ./ibdata1 error: 11
2020-06-29  0:17:48 0 [Note] InnoDB: Check that you do not already have another mysqld process using the same InnoDB data or log files.
2020-06-29  0:17:49 0 [ERROR] InnoDB: Unable to lock ./ibdata1 error: 11
2020-06-29  0:17:49 0 [Note] InnoDB: Check that you do not already have another mysqld process using the same InnoDB data or log files.
2020-06-29  0:17:49 0 [Note] InnoDB: Unable to open the first data file
2020-06-29  0:17:49 0 [ERROR] InnoDB: Operating system error number 11 in a file operation.
2020-06-29  0:17:49 0 [ERROR] InnoDB: Error number 11 means 'Resource temporarily unavailable'
2020-06-29  0:17:49 0 [Note] InnoDB: Some operating system error numbers are described at https://mariadb.com/kb/en/library/operating-system-error-codes/
2020-06-29  0:17:49 0 [ERROR] InnoDB: Cannot open datafile './ibdata1'
2020-06-29  0:17:49 0 [ERROR] InnoDB: Could not open or create the system tablespace. If you tried to add new data files to the system tablespace, and it failed here, you should now edit innodb_data_file_path in my.cnf back to what it was, and remove the new ibdata files InnoDB created in this failed attempt. InnoDB only wrote those files full of zeros, but did not yet use them in any way. But be careful: do not remove old data files which contain your precious data!
2020-06-29  0:17:49 0 [ERROR] InnoDB: Plugin initialization aborted with error Cannot open a file
2020-06-29  0:17:49 0 [Note] InnoDB: Starting shutdown...
2020-06-29  0:17:50 0 [ERROR] Plugin 'InnoDB' init function returned error.
2020-06-29  0:17:50 0 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2020-06-29  0:17:50 0 [Note] Plugin 'FEEDBACK' is disabled.
2020-06-29  0:17:50 0 [ERROR] Unknown/unsupported storage engine: InnoDB
2020-06-29  0:17:50 0 [ERROR] Aborting

The solution
Website query Error code 11
Operating System Error Codes – MariaDB Knowledge Base
https://mariadb.com/kb/en/operating-system-error-codes

It’s no use trying again
An attempt was made to remove the deleted error file

cd /var/lib/mysql
ll

total 188492
-rw-rw---- 1 mysql mysql    16384 Jun 28 22:43 aria_log.00000001
-rw-rw---- 1 mysql mysql       52 Jun 28 22:43 aria_log_control
-rw-rw---- 1 mysql mysql     7007 Jun 28 22:43 ib_buffer_pool
-rw-rw---- 1 mysql mysql 79691776 Jun 28 22:49 ibdata1
-rw-rw---- 1 mysql mysql 50331648 Jun 28 23:18 ib_logfile0
-rw-rw---- 1 mysql mysql 50331648 Jun 22 09:17 ib_logfile1
-rw-rw---- 1 root  root  12582912 Jun 28 23:18 ibtmp1
-rw-rw---- 1 mysql mysql        0 Jun 22 09:28 multi-master.info
drwx------ 2 mysql mysql     4096 Jun 22 09:17 mysql
-rw-rw---- 1 mysql mysql      351 Jun 28 21:52 mysql-bin.000001
-rw-rw---- 1 mysql mysql      351 Jun 28 22:19 mysql-bin.000002
-rw-rw---- 1 mysql mysql      351 Jun 28 22:31 mysql-bin.000003
-rw-rw---- 1 mysql mysql      351 Jun 28 22:32 mysql-bin.000004
-rw-rw---- 1 mysql mysql      351 Jun 28 22:43 mysql-bin.000005
-rw-rw---- 1 mysql mysql       95 Jun 28 22:32 mysql-bin.index
-rw-rw---- 1 mysql mysql        0 Jun 28 22:43 mysql-bin.state
drwx------ 2 mysql mysql     4096 Jun 22 09:17 performance_schema

Remove or delete the following three files :(note the backup)

ibdata1、ib_logfile0、ib_logfile1

Restart the mariadb/mysql