Linked Clones the Easy, Scalable Way: Why View Composer Rocks
Update: Still using VMware View Composer linked-clone technology? It’s time to try a new way of provisioning desktops. Get started with VMware Instant Clone Technology in VMware Horizon 7.
In searching for information about View Composer, I found that VMware has not published many articles on this subject. When I asked around, I heard people say, “Composer just works,” or “It is a feature of View everyone knows how to use.” This led me to think that maybe the time has come for Composer to have its day in the sun on this blog.
What Does Composer Do?
Simple answer: It provides linked clones.
Longer answer: View Composer is a feature of Horizon with View which allows administrators to easily manage pools of similar desktops by creating golden master or parent images that share a common virtual disk. All cloned desktops linked to a parent image can be patched or updated through View Administrator by simply updating the single master image, without affecting users’ settings, data, or applications. The process looks something like this:
Why Does Composer Rock?
The cool part is that even though Composer is seen as just a feature of View, it is the most scalable linked-clone technology on the market. And you do not have to take my word for it! In what is believed to be the world’s largest documented VDI deployment, the Bank of Tokyo-Mitsubishi-UFJ (BTMU), has deployed over 60,000 virtual desktops—and more are on the way—all using Horizon with View and Composer.
BTMU and others have chosen View and Composer because of these enterprise-class scalability, reliability, and performance advantages (among other reasons):
- Scale linked clones to master images by over 50:1, depending on your storage array and setup.
- Control how aggressively linked-clone virtual desktops can be assigned to the free space available on the datastore.
- Relocate virtual images to new logical disks (LUNs) with a single mouse click to optimize storage resources.
- Leverage storage cache to improve virtual desktop performance.
- Leverage the advanced functionality of VMware vSphere, the industry’s leading, most reliable virtualization platform.
To make it easier for users to deploy, Composer has several large-scale published reference architectures that demonstrate the ease of deployment and scalability, and quantify the value delivered. This table summarizes some of the information you can find in these documents:
For some who think scalability is not that thrilling, there is also the intuitive and seamlessly integrated management between Composer and the View Administrator console. The oneness of the integration makes all the difference in how easy it is to provision and manage virtual machines.
You invoke Composer from a drop down in View Administrator, and the process is simple for defining a desktop pool with Composer. Composer really is just an integrated feature. Maybe that is why no one writes that much about it.
However, some bloggers are taking notice of the value of Composer. Rob Zylowski said in his 2012 virtual-desktop-management blog: “Still, View Composer is a very elegant solution to managing a shared non-persistent infrastructure, implemented in a simple and straightforward manner that works reliably.”
How Does Composer Compare to the Competition?
One popular solution on the market is based on antiquated technology. The Citrix Provisioning Services (PVS) is a provisioning technology that has been around for decades. PVS requires a separate infrastructure, uses PXE boot, and lacks integration to leverage vSphere for storage and IOPS savings. View Composer is integrated with View and vSphere, leveraging key features such as Content-Based Read Cache for decreasing VDI boot times, storage space reclamation for using less storage, and Virtual SAN integration for easy management of local storage.
Citrix introduced Machine Creation Services (MCS) in 2010 as a more up-to-date provisioning technology that more closely compares to the Composer linked-clone approach. According to people familiar with MCS, the issue is that MCS is limited in scalability and lacks large-scale deployment proof and capabilities. In searching for reference architectures and customer success stories for MCS, I have reached the same conclusion.
If you are interested in seeing how Composer compares to these two Citrix provisioning technologies, here are some fun YouTube videos that demonstrate the user experience of installing and provisioning ten virtual machines:
Purpose-Built for VDI
One last advantage of Composer is that it was purpose-built for VDI. While that may seem like an obvious requirement, not all solutions out there can claim VDI as their first love. And this capability does make a difference.