If you need to do fulltext searches, MyISAM is your only choice. If you switch to InnoDB, you might have to split some tables and rewrite some code to use both engines.
Note that the full-text modes only support prefix searching. For postfix you could either reverse the field your looking for (redundant data in your table), or use something like sphinx; which nowadays has great integration with MySQL.
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If you need to do fulltext searches, MyISAM is your only choice. If you switch to InnoDB, you might have to split some tables and rewrite some code to use both engines.
Note that the full-text modes only support prefix searching. For postfix you could either reverse the field your looking for (redundant data in your table), or use something like sphinx; which nowadays has great integration with MySQL.