Default to MyISAM instead of InnoDB in Drupal 7 Can I make Drupal default to MyISAM for new tables instead of InnoDB? Except for hacking the core, that is.
The quickest and dirtiest way to get all Drupal data into MyISAM perform the following:

Make a backup of /var/lib/mysql before doing these steps

step 1. mysqldump all data out of mysql

step 2. remove all folders and files from /var/lib/mysql, but leave the /var/lib/mysql/mysql alone because it contains user grants.

step 3. add this line in /etc/my.cnf

[mysqld]
skip-innodb


step 4. service mysql restart

step 5. reload mysqldump file back into data into mysql database

UPDATE 2011-10-04 04:28 EDT

step 1. Set Default Storage Engine to MyISAM

add this line in /etc/my.cnf 

[mysqld]
default-storage-engine = MyISAM


step 2. service mysql restart

Give it a Try !!!