So i am planned to go for one more Centos5 server with cluster.Can any one suggest me how to design it either i have to go for common storage for storing all global files or i need to synchronize both the server periodically by running instance on local disk of both the servers.
You could also make them peer caches of one another and you could also use Linux Virtual Server .. part of the Cluster Suite to load balance .. although you would need to make sure that you have persistence enabled.