I believe it is the same as the max number of initiator records per storage system.  Which is 512.  this can be found in the CLARiiON Open Systems Configuration Guide on powerlink: Home > Products > Hardware/Platforms > CLARiiON CX4 Series > Matrices

Please note that your hosts sharing luns must have some sort of clustering software enabled and configured to be a supported configuration.  Directions on connecting your host can be found on  Home > Support > Technical Documentation and Advisories > Host Connectivity/HBAs > Installation/Configuration

or you can create a customizable host connectivity document by going to http://www.emc.com/microsites/clariion-support/central.htm

Thanks