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
For Lenovo Storage V3700 V2 and Lenovo Storage V3700 V2 XP: https://datacentersupport.lenovo.com/us/en/products/storage/lenovo-storage/v3700v2/6535
For Lenovo Storage V5030: https://datacentersupport.lenovo.com/us/en/products/storage/lenovo-storage/v5030/6536