euroNAS SAN Cluster uses for the communication with the FC initiators (clients) MPIO/ALUA. You have to make sure that your client is properly configured for multipath.
Windows server versions support multipath and need to be configured manually (MPIO service must be installed). VMware ESX and MAC XSAN will recognize multipath automatically.
Citrix Xen and Linux needs manuall configuration (check article “How to configure Citrix Xen for euroNAS SAN Cluster”)