The big is that InnoDB supports transaction
InnoDB supports some newer features: Transactions, row-level locking, foreign keys
InnoDB is for high volume, high performance
Most people use MyISAM if they need speed and InnoDB for data integrity. You can use more than one or any combination of these table types in your database. Remember to asses the needs of your application before building it. Even though MyISAM is faster than InnoDB in the MySQL world, InnoDB is fast compared to any database engine.With InnoDB you get transactions, speed and integrity three features not usually used in the same sentence.
InnoDB has been designed for maximum performance when processing large data volumes. Its CPU efficiency is probably not matched by any other disk-based relational database engine.
Fully integrated with MySQL Server, the InnoDB storage engine maintains its own buffer pool for caching data and indexes in main memory. InnoDB stores its tables and indexes in a tablespace, which may consist of several files (or raw disk partitions). This is different from, for example, MyISAM tables where each table is stored using separate files. InnoDB tables can be of any size even on operating systems where file size is limited to 2GB.
完全整合，InnoDB存储引擎与MySQL服务器在主内存中缓存数据和索引维护自己的缓冲池。 InnoDB的表和索引存储在表空间中，这可能包括几个文件（或原始磁盘分区）。这是不同的，例如，MyISAM表，其中每个表存储使用单独的文件中。 InnoDB表可以是任何尺寸，即使文件大小限制为2GB的操作系统上。