Finally I have finish install openmeetings on CentOS server with some notice :

  1. Use ulimit to make Red5 server start normaly , event it use high performance
  2. During this installation I found interesting command for linux , sync; echo 3 > /proc/sys/vm/drop_caches , it will clear RAM cache, if we need to clear linux memcache
  3. After access install page process (http://host:5080/openmeetings/install) we need to change the database and table char set to UTF-8 that already created automatically by hibernate process.
  4. The method of char set changing, I export the database to SQL file, change the charset to UTF-8 using text editor, I drop the table that already created then I import modified SQL file to database.