EMA8000: node2 dropped its cluster group and is unable to recconect

[CA1133091]

First started by getting an event ID 1026 The Driver has detected a path failure to Subsystem ID... and was followed by many event ID 15's that state The device, \Device\HarddiskX\DRX, is not ready for access yet.
When trying to bring the any of the cluster groups online on node2 it fails at the disks and promptly goes back to the working node1.
Doing a "show connections" on the ema8000 shows all four HBA's (two from each node) OL.

[CA1135231]

Sounds to me that somehow both paths from node2 are broken. Doing a "show connections" on the HSG80 won't help much, the HSG80 is rather dumb in this area. The connections stay "ONLINE" until the HSG80 is rebooted.
Try doing a "switchshow" on the switches that node2 connects to and see if you've got the ports online. Next, I'd poke around in Secure Path Manager to see if any paths can be repaired.
It's a start, keep us posted.
/charles