If you get this error in mySQL:
/usr/libexec/mysqld: Table './mysql/' is marked as crashed and last (automatic?) repair failed [ERROR Fatal error: Can't open and lock privilege tables: Table './mysql/' is marked as crashed and last (automatic?) repair failed mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
Run this:
myisamchk -r /var/lib/mysql/mysql/*.MYI