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What is IntelliCache ?

IntelliCache is a XenServer feature that can be used in a XenDesktop deployment to cache temporary and non‐persistent operating‐system data on the local XenServer host. IntelliCache is available for Machine Creation Services (MCS)‐based desktop workloads that use NFS storage.

In a typical XenDesktop configuration (without IntelliCache), desktop VMs read the operating‐system data from a master image on a costly shared storage array. When IntelliCache is enabled, a portion of the virtual‐machine runtime reads and writes occur on low‐cost local storage: XenServer caches the operating‐system files on its local hard drive in a Read Cache. Likewise, when IntelliCache is enabled, each desktop VM writes to its own Write Cache on the local host, preventing writes to shared storage. As a result of caching on local storage, when IntelliCache is configured for a pooled desktop, it significantly reduces the load on the remote storage and the amount of network traffic.

intellicache_start

How to enable IntelliCache in XenServer ?

Enabling on Host Installation

  1. When installing XenServer, select Enable thin provisioning (Optimized storage for XenDesktop).
  2. XenServer Setup then creates a Storage Repository which has thin provisioning enabled.  This option will change the default local storage type from LVM to EXT3

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Converting an Existing Host to Use Thin Provisioning

To destroy an existing LVM based local SR, and replace it with a thin provisioned EXT3 based SR, enter the following  commands.

Warning:
These commands will destroy your existing local SR, and VMs on the SR will be permanently deleted.

localsr=xe sr-list type=lvm host=<hostname> params=uuid --minimal
echo localsr=$localsr
pbd=xe pbd-list sr-uuid=$localsr params=uuid --minimal
echo pbd=$pbd
xe pbd-unplug uuid=$pbd
xe pbd-destroy uuid=$pbd
xe sr-forget uuid=$localsr
sed -i “s/’lvm’/’ext’/” /etc/firstboot.d/data/default-storage.conf
rm -f /etc/firstboot.d/state/10-prepare-storage
rm -f /etc/firstboot.d/state/15-set-default-storage
service firstboot start
xe sr-list type=ext

To enable local caching, enter the following commands:

xe host-disable host=<hostname>
localsr=xe sr-list type=ext host=<hostname> params=uuid --minimal
xe host-enable-local-storage-caching host=<hostname> sr-uuid=$localsr
xe host-enable host=<hostname>

How to enable IntelliCache in XenDesktop

  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 device.

intellicache_xendesktop

 

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