The multipath driver is installed as part of the Citrix XenServer software.
The following Web site provides a general overview of multipathing on Citrix XenServer 5.0:
http://support.citrix.com/article/CTX118791
The following Web site provides the most current information about the IBM® configuration file (multipath.conf) for SAN Volume Controller:
www.ibm.com/storage/support/2145