default table type = innodb is stable??

[Hiu Yen Onn]

hi,

i have a machine with 6G memory, loaded with RHEL4. now, my question is 
mysql support innodb as the default table type? will be stable running 
RHEL4?
i saw /usr/share/mysql/my-innodb-heavy-4G.cnf file, then, i replace the 
existing one (/etc/my.cnf). but, it failed to start the mysql server. 
please advise. thanks?