This article describes how to use IntelliCache with XenDesktop.

Background

XenServer 5.6 Feature Pack 1 includes new features that optimize the XenServer hypervisor to use in XenDesktop hosted virtual machine deployments. IntelliCache feature of XenServer caches temporary and non-persistent files for desktop workloads on the local disk of the host server.

In caching locally, a portion of runtime reads and writes of the virtual machine might occur in low cost server attached storage rather than transmitting across more expensive Network Attached Storage (NAS) or Storage Area Network (SAN) resources. As a result, IntelliCache might reduce 90% of the requirements for central storage. The combination of IntelliCache and Machine Creation Services allows administrators to deploy and manage all virtual machines as a thin copy of a master Virtual Machine and build a cache of that image on host servers.

Administrators can still perform live migration of dedicated Virtual Machines when required, as the local state is only a cache so a Virtual Machine can easily fall back to central storage whenever required. In addition, when the storage capacity of the local disk is reached, IntelliCache falls back to a safe mode and transfer all reads and writes back to the shared storage.

Citrix recommends to use a high performance local storage device to ensure the fastest possible data transfer. To use IntelliCache, you must have at least both XenServer 5.6 Service Pack 2 and XenDesktop 5 Service Pack 1 installed, and enable the functionality in both XenServer and XenDesktop.

Instructions

To Enable IntelliCache in XenServer

Select Enable thin provisioning (Optimized storage for XenDesktop) when installing XenServer. The installer will then create a Storage Repository which has thin provisioning enabled. You cannot enable thin provisioning after a non-thin provisioned Storage Repository has been created. This includes the case where you are upgrading from an older version of XenServer.

Note: Citrix does not support mixed pools of servers that have IntelliCache enabled and servers that do not.

For further information on using IntelliCache and how to convert an existing host to use Thin Provisioning, refer to CTX129387 - XenServer 5.6 Service Pack 2 Installation Guide

IntelliCache is disabled by default in XenDesktop. You can enable it when you are adding a host, provided the XenServer pool is XenServer 5.6 Service Pack 2 or later. You can update the setting only when the host is created; you cannot disable IntelliCache later. The option to enable IntelliCache is not available if you are configuring a site using Quick Deploy.

1. When you are adding a XenServer host and you are prompted for the type of storage to use, select Shared.

2. Select Use IntelliCache to reduce load on the shared storage.