How to change default storage engine in MySQL ?

The default storage engine can be changed at server startup or at runtime:

• The default storage engine can be specified at server startup with the --default-storage-engine option.
• For a running server, an administrator who has the SUPER privilege can change the default storage engine globally for all clients by setting the global storage_engine system variable:
  

  SET GLOBAL storage_engine = engine_name;

  Setting the storage engine this way affects any client that connects after the statement executes. Clients that are connected at the time of statement execution are unaffected.
• Any client can change its own default storage engine by issuing either of these statements:

  SET SESSION storage_engine = engine_name;
  SET storage_engine = engine_name;