 Pre-FC4700 Access Logix configurations handle "fairness" (access time for each server to the array) by default in the following manner. The storage system processes I/O requests from servers on a first-come, first-served basis. With multiple servers contending for the use of a storage system, a server with disproportionate processing demands might monopolize storage-system resources. In addition, operating systems, such as Windows NT, use scheduling policies that slow down storage-system access within a storage area network (SAN). To provide each server on a SAN with a fair amount of storage-system resources, shared storage systems have an optional fairness algorithm. This algorithm tries to manage the I/Os accepted by the storage system so that servers accessing different LUNs with similar data access patterns will get similar I/O throughput.   The method for handling fairness for FC4700 and CX-series arrays has changed. "Fairness" on these arrays is based on an EMC proprietary algorithm within Base Software. The algorithm allocates resources on a per LUN and per port basis, dynamically maintaining the allocation of these resources. Since this feature of CLARiiON Base Software is handled internally, it is no longer a customer-manageable option. 
Hi All,  I looked student guide, and found "Enforce Fail Access" option. It can enable or disable fair access for all hosts connected to thestorage system.   Colud you give me more detailed explanation?  Thank you, Dennis Dai
Storage System Properties – Storage Access Tab - Enforce Fair Access