Cluster Crashed. Urgent help needed (4 replies)

All,
We are operating Cluster with 6 Datanodes, which just crashed.
We tried to restart it but got this kind of messages:


Node 4: Forced node shutdown completed. Occured during startphase 1. Caused by error 2353: 'Insufficent nodes for system restart(Restart error). Temporary error, restart node'.
Node 7: Forced node shutdown completed. Occured during startphase 1. Caused by error 2308: 'Another node failed during system restart, please investigate error(s) on other node(s)(Restart error). Temporary error, restart node'.
Node 5: Forced node shutdown completed. Occured during startphase 1. Caused by error 2308: 'Another node failed during system restart, please investigate error(s) on other node(s)(Restart error). Temporary error, restart node'.


What is the best option to evaluate, what happened and how are we able to solve the situation.
I'm willing to pay for excellence!

Thank You