Cluster does not have quorum or some nodes are not communicating

Hi All,

We have 4 EMC Isilon nodes when we check the status on cli we got the the warning "Cluster does not have quorum or some nodes are not communicating" with 2 nodes showing down status which are first and fourth nodes in the cluster.

When we checked physically the fourth node enter to the EFI Shell with a message "map: Cannot find required map name." the same node internal infiniband connection LED is off and the Network Fiber LED is off and the HDs aren't LEDs aren't flashing.

The first node keep showing continues messages on the CLI with some errors like "Error 5, Retries exhausted" and "Error 6, Synchronization request failed" the same node internal infiniband connection LED is blinking and the Network Fiber LED is off and the HDs aren't LEDs aren't flashing.

I appreciate any help in this issue.

Regards,