We have indexes dedicated to queries on the master and indexes dedicated to queries on the slave.

Would be possible to create different indexes for a master and its slaves to save space and enhance write performance ?
Creating an index in a slave raises an error in "mongod".
Could the replication feature only replicate data, and not indexes creation/ deletion ?

Original question on Google Groups: http://groups.google.com/group/mongodb-user/browse_thread/thread/c2ebf3bfd09cf44e