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.
How to enable IntelliCache in XenServer ?
Enabling on Host Installation
- When installing XenServer, select Enable thin provisioning (Optimized storage for XenDesktop).
- 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
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.
These commands will destroy your existing local SR, and VMs on the SR will be permanently deleted.
xe sr-list type=lvm host=<hostname> params=uuid --minimal
xe pbd-list sr-uuid=$localsr params=uuid --minimal
xe pbd-unplug uuid=$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>
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
- When you are adding a XenServer host and you are prompted for the type of storage to use, select Shared.
- Select Use IntelliCache to reduce load on the shared storage device.