Re: InnoDB doesn't work

[Rick James]

Look in mysqld.err -- the reason for failure should be there.

A likely cause... If you changed
innodb_log_file_size = 100M
you need to
1. stop mysql cleanly
2. delete the old iblog files
3. restart mysql -- it will rebuild them of the new size.

Note -- changing the _default_ engine will NOT change any _existing_ tables. That needs to be done with individual
ALTER TABLE foo ENGINE=InnoDB;
statements.

Note also, InnoDB's disk footprint is typically 2x-3x bigger than MyISAM.