If you have a large database dump file that you need to import, you will need to change the max size that can be imported. This is not handled by the default php.ini file on the server, so increasing that will not help.
To increase it, login to the WHM, click on tweak settings, then click on the PHP tab and change both of these settings.
cPanel PHP max POST size (Minimum: 55; Maximum: 2,047)
cPanel PHP max upload size (Minimum: 50; Maximum: 2,047)
Once you have changed these, you should restart the cpanel services. Now when importing the max filesize will be increased to whatever you set this to.