How two or more clusters in two diffferent data centers can communicate to each other . I have two clusters in two different data centers and i want to make them communicate.Can i do the vmotion across two different custers in two different datacenters or it will only be possible in vsphere 5 ..
Yeah you are talking about long distance vMotion. It is possible and has been supported for a long time now. Depending on your bandwidth, latency and a few other factors it works well.
Here is an old yellowbricks link. I don't think much has changed.