Citrix’s Machine Creation Services, or MCS, is one of the industry’s best mechanisms for delivering virtual desktops at scale.
However, If you are using a hypervisor that is not optimized for Citrix, virtual desktop reboots and Machine Catalog updates might take more time while putting more load on your storage. This can lead to a poor user experience, frustrated administrators, and potential delays in go to market activities that relay on rapidly expanding your Citrix deployment.
MCS delivers the ability to easily spin up many virtual desktops or virtual applications servers from a single golden image. Its one of the reasons admin around the world love Citrix and why Citrix is a leading DaaS provider.
MCS is dependent on storage to deliver the images. Without IntelliCache, every virtual machine on the hypervisor will pull its image from the storage on every boot, reboot, and Machine Catalog Update. This can put high load on remote storage and the storage load needs to be considered when designing or expanding your Citrix deployment.
To avoid storage bottlenecks and boot storms, XenServer developed IntelliCache to help you get the most out of your existing infrastructure with Citrix Machine Creation Services.
What can IntelliCache do?
Using the XenServer platform with IntelliCache to provide the MCS workloads can make significant improvements on the storage load, and also result in much faster VM boot performance.
If you want to see a demonstration of the impact of the IntelliCache on MCS workloads, check out this side-by-side demo:
How does the IntelliCache work?
XenServer provides a feature called IntelliCache to help reduce the load on the remote storage by making use of the local storage in the hypervisor hosts to provide a persistent read cache of the data being read from the master image and can significantly reduce the load on the central storage and also a write through cache for the updates from the VM.
This will optimize storage load for machines created using MCS when thin provisioned onto storage without impacting the agility of the machines. The VMs can be started on any host that has access to the storage being used, the cache will be recreated using local host storage on whichever host is selected.
When using MCS you are provisioning and distributing many identical machines, as long as you are not using a full clone method they all share a common master image. All these machines will read their disk content directly from the storage that they are provisioned onto.
VMs Provisioned with MCS using the thin clone technology will look like this.
When using IntelliCache the read and write paths for the data will look like this, diverting load from the remote storage to local storage.
This is all transparent which means as far as the VM is concerned it is still using disks on the NFS server which allows them to continue to be load balanced across the hosts in the XenServer pool and needs no maintenance or management by the administrator.
How easy is this to use?
You can watch the video below to see how effective the IntelliCache is in action and see how simple it is to configure and use it..
You can test it out yourself in the XenServer Trial Edition available here https://www.xenserver.com/downloads#download.
All you need to do it make sure that the XenServer hosts were installed to use EXT rather than LVM. This can be done at install time or after installation see https://docs.xenserver.com/en-us/xenserver/8/storage/intellicache.html for details.
Then make sure when you create the connection to the XenServer in the WebStudio UI that you select the ‘Use IntelliCache’ option as shown below. All machines provisioned using this hosting definition will gain these optimizations.
This will work for any usage of NFS storage when there is local storage in the hosts and will work for all types of provisioned machines except those made using the full clone method.
Check out the IntelliCache documentation for more information: https://docs.xenserver.com/en-us/xenserver/8/storage/intellicache.html