Can't start mysqld service after changing datadir

I have an AWS EC2 instance with RHEL 7 on which I installed mysql-5.5 on xvda. Its datadir is under /var/lib/mysql (as is the default). *I am importing dumps from a database on version 5.5.29 and the currently installed version is 5.5.60* A larger volume xvdf has been attached since I was running out of space and mounted it at /data_drive Then followed these steps to change the data directory: - Stop mysqld and verify if it had stopped - used rsync -av /var/lib/mysql /data_drive to move folder with permissions - moved the older mysql data directory to a backup file on the xvda (original volume) - Edited /etc/my.cnf to change the [mysqld] block to reflect the new location in both datadir and socket `datadir=/data_drive/mysql socket=/data_drive/mysql/mysql.sock` - added the client block at the end of the file `[client] port=3306 socket=/data_drive/mysql/mysql.sock` - saved the file and then tried to restart the mysqld service as root user and non-root user but it won't start. Here is the /var/log/mysqld.log output from the relevant timestamps: 180713 19:27:57 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended 180713 20:20:37 mysqld_safe Logging to '/var/log/mysqld.log'. 180713 20:20:37 mysqld_safe Starting mysqld daemon with databases from /data_drive/mysql 180713 20:20:37 [Warning] Can't create test file /data_drive/mysql/ip-10-0-0-180.lower-test 180713 20:20:37 [Note] /usr/sbin/mysqld (mysqld 5.5.60) starting as process 18669 ... 180713 20:20:37 [Warning] Can't create test file /data_drive/mysql/ip-10-0-0-180.lower-test 180713 20:20:37 [Warning] Can't create test file /data_drive/mysql/ip-10-0-0-180.lower-test 180713 20:20:37 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld: Can't find file: './mysql/plugin.frm' (errno: 13) 180713 20:20:37 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 180713 20:20:37 InnoDB: The InnoDB memory heap is disabled 180713 20:20:37 InnoDB: Mutexes and rw_locks use GCC atomic builtins 180713 20:20:37 InnoDB: Compressed tables use zlib 1.2.3 180713 20:20:37 InnoDB: Using Linux native AIO 180713 20:20:37 InnoDB: Initializing buffer pool, size = 128.0M 180713 20:20:37 InnoDB: Completed initialization of buffer pool 180713 20:20:37 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. InnoDB: File name ./ibdata1 InnoDB: File operation call: 'open'. InnoDB: Cannot continue operation. When I ran sudo mysql_upgrade it gave the following output: Looking for 'mysql' as: mysql Looking for 'mysqlcheck' as: mysqlcheck Error: Failed while fetching Server version! Could be due to unauthorized access. FATAL ERROR: Upgrade failed This is how the /data_drive/mysql directory looks at the moment: [ec2-user@ip-10-0-0-180 mysql]$ ls -al /data_drive/mysql/ total 5921812 drwxr-xr-x. 4 mysql mysql 4096 Jul 13 18:45 . drwxr-xr-x. 5 ec2-user root 4096 Jul 13 18:46 .. -rw-rw----. 1 mysql mysql 6053429248 Jul 13 18:45 ibdata1 -rw-rw----. 1 mysql mysql 5242880 Jul 13 18:45 ib_logfile0 -rw-rw----. 1 mysql mysql 5242880 Jul 13 18:35 ib_logfile1 drwx------. 2 mysql root 4096 Jul 12 19:42 mysql drwx------. 2 mysql mysql 4096 Jul 12 19:42 performance_schema