Guest blog by Mark Slater, Cloud Architect, OGL
OGL is the premier provider of IT support and solutions to over 1,000 businesses throughout the UK. We pride ourselves on delivering superior services and support as customer satisfaction is our number one priority. We are constantly looking for technologies to enhance our offerings. Recently, we embarked on a journey to provide a scalable desktop service on a multi-tenant platform. We needed a platform that was flexible in provisioning new applications for our customers and their end users. And we needed to deliver desktops and applications as fast as possible inside our multi-tenant environment.
We were in good shape with our current desktop and app delivery system using Citrix, but were looking for ways to optimize our processes and lower costs. In searching for tools to help us enhance our offering, we came across CloudVolumes–now VMware App Volumes. App Volumes piqued our interest because the technology provided a real time application delivery system. We were managing many templates or “Gold Images” with Citrix Provisioning Services (PVS). If we continued to grow, the number of templates we would have to manage would also continue to grow. We also wanted to reduce the storage footprint of this platform. When we learned App Volumes could help us with these time and cost savings and support this within a multi-tenant VDI model, we were intrigued. We are still using App Volumes today and here is why.
Storage Savings with App Volumes
With PVS, if we were to embed applications for each customer we delivered apps to, within a separate “Golden Image”, we would literally have about 40 golden images to manage. And the typical “Golden image” with OS and all the customers’ applications installed would amount to about 40GB. Each of these images tends would also have test/maintenance incremental versions, created during image updates.
With such a large number of “Golden Images” per PVS server, the I/O load on the server would also increase and require faster storage. And because PVS servers use in-memory caching for disk images, the RAM size on the PVS servers would need to be increased significantly to ensure an acceptable level of performance when streaming desktops.
And this is where App Volumes came in. With App Volumes we were able to streamline the number of images we managed from 40 down to 2, and use only 100GB of disk space on each PVS server. This has meant that we have been able to use lower performance disks with less RAM installed on the PVS servers. We also have eliminated the need to duplicate the same application across customers and are now only using approximately 300 GB of storage for App Volumes AppStacks. This equates to just over a 7x reduction in storage requirements.
Time Savings with App Volumes
In our old model, each “Golden Image” would also have needed to undergo regular maintenance to address the following:
- Windows OS updates
- Application updates
- Any new applications
Within Citrix PVS this would involve creating a maintenance version of the image, booting from the maintenance version, applying updates and then testing. This resulted in a lot of duplicative work: for example a common application such as Adobe Acrobat would need to be updated in all 40 “Golden Images”. Conservatively, this would take about one hour per week per image, so in our multi-tenant environment this would be 40 hours per week or the equivalent of one full time employee. And even if you were only updating a single application you would need to update the entire “Golden Image”.
Using App Volumes, we can run two “Golden Images” which contain the OS and a few applications which are common across all customers (e.g. Adobe Reader, Flash Player, Java). All other applications are then delivered using App Volumes with the ability to provision an application and deliver it to multiple customers, thus saving considerable time when updating the “Golden Images” and only having to update a single copy of an application once across multiple customers.
The other area where we have been able to save time vs. using other application virtualization technologies such as ThinApp or AppV, has been around application provisioning and ongoing support. This has especially been true for applications that require deep OS integration or inter-operability with other applications. Applications deployed using App Volumes appear as though they are natively installed to the underlying OS and other applications. This simplifies application support and also allows 3rd party software vendors to carry out remote support without the added complication of having to deal with the application running in a semi-isolated bubble, reducing the risk of that the software vendor will say “Sorry, we don’t support the application running that way.”
Using VMware App Volumes, we are able to provide real-time application delivery to many different virtualized environments, including VMware Horizon and Citrix XenApp and XenDesktop environments. We have saved over 7x in storage capacity and reduced the number of golden images we manage from 40 to 2. And now that App Volumes is a part of the Horizon Application Management Bundle, we will look at ways to enhance our Citrix environment even further!
