Integrated StorageLink was retired in XenServer 6.5.
Background: XenServer 6 introduced Integrated StorageLink Capabilities. It replaces the StorageLink Gateway technology used in previous editions and removes the requirement to run a VM with the StorageLink components. It provides access to use existing storage array-based features such as data replication, de-duplication, snapshot and cloning. Citrix StorageLink allows to integrate with existing storage systems, gives a common user interface across vendors and talks the language of the storage array i.e. exposes the native feature set in the storage array. StorageLink also provides a set of open APIs that link XenServer and Hyper-V environments to third party backup solutions and enterprise management frameworks. There is a limited HCL for StorageLink supporting arrays. Details: http://bit.ly/1xS2J0m