Database Directory storage is full need to change link it to new Partition

Question

My mysql Database Directory size is full. So I want to change it to another partition where there is large amount of space. The database version am using is MySQL 5.7.23 and OS is CentOS 7.

After searching internet i got 2 solutions. First one as follows:

Firstly,I created a Systemlink pointing to the new drive. Then I tried to start mysql, it fails everytime when I try to start. On removing systemlink it will start.

The error am getting is

[Note] InnoDB: Highest supported file format is Barracuda.
2018-08-21T10:08:04.839330Z 0 [ERROR] InnoDB: Operating system error number 
13 in a file operation.
2018-08-21T10:08:04.839349Z 0 [ERROR] InnoDB: The error means mysqld does 
not have the access rights to the directory.
2018-08-21T10:08:04.839360Z 0 [ERROR] InnoDB: os_file_readdir_next_file() 
returned -1 in directory ./, crash recovery may have failed for some .ibd 
files!
2018-08-21T10:08:04.839385Z 0 [ERROR] InnoDB: Plugin initialization aborted 
with error Generic error
2018-08-21T10:08:05.440529Z 0 [ERROR] Plugin 'InnoDB' init function returned 
error.
2018-08-21T10:08:05.440597Z 0 [ERROR] Plugin 'InnoDB' registration as a 
STORAGE ENGINE failed.
2018-08-21T10:08:05.440610Z 0 [ERROR] Failed to initialize builtin plugins.
2018-08-21T10:08:05.440617Z 0 [ERROR] Aborting

2018-08-21T10:08:05.440665Z 0 [Note] Binlog end
2018-08-21T10:08:05.440770Z 0 [Note] Shutting down plugin 'CSV'
2018-08-21T10:08:05.441349Z 0 [Note] /usr/sbin/mysqld: Shutdown complete

Secondly, https://www.digitalocean.com/community/tutorials/how-to-move-a-mysql-data-directory-to-a-new-location-on-ubuntu-16-04 I followed this url and after that when tried to start mysql keep on getting this error Cant connect to localhost (111) (Error: 2003). This time nothing is showing in mysqld.log file

Answer 1

Here is the key:

2018-08-21T10:08:04.839360Z 0 [ERROR] InnoDB: os_file_readdir_next_file() 
returned -1 in directory ./, crash recovery may have failed for some .ibd 
files!

It says, it can't traverse the directory containing the database files, with the error code -1. Error -1 means

permission denied

The user on which your mysql server is running, should have access to the directory. On most Linuxes, the command is: chown mysql:mysql -Rc /var/lib/mysql as root.