ubuntu mysql mysqld File databinlogmysql-binindex not found OS errno 13 - Permission denied

This error message indicates that the MySQL server is unable to find the mysql-bin.index file in the specified location due to insufficient permissions.

To resolve this issue, you can follow these steps:

1. Check the ownership and permissions of the /data/binlog directory. Make sure that the MySQL user (usually mysql) has the necessary permissions to access and modify files in that directory.

   ls -ld /data/binlog
   

   The output should show the owner and group of the directory, as well as the directory permissions. If the owner is not mysql or if the permissions are too restrictive, you need to change them.

2. Change the ownership and permissions of the /data/binlog directory if necessary. You can use the chown and chmod commands to accomplish this.

   sudo chown mysql:mysql /data/binlog
   sudo chmod 755 /data/binlog
   

   The first command changes the ownership of the directory to the mysql user and group, while the second command sets the permissions to allow read, write, and execute for the owner, and read and execute for others.

3. Restart the MySQL service to apply the changes.

   sudo service mysql restart
   

Once the MySQL service restarts, it should be able to find the mysql-bin.index file without any permission denied errors