Given a pandemic situation like Covid-19, Virtual Desktops have emerged to become a key player in enabling users to work remotely from home.
If you are an avid user of the Virtual Desktop (VDI) technology, you would have definitely heard a lot about instant and linked clones. These are the technologies that enables the cloning of VMs into multiple copies.
To set things straight, there are typically 3 types of provisioning technology:
- Manual Provisioning
- Linked Clones
- Instant Clones
We will take a look briefly at these 3 different provisioning process and see how they compare to each other.
In a manual provisioning process, like the name suggests, it is done in a manual fashion where you create VMs by either cloning an existing VM or manually setting up (install + configure an OS…etc.) just to create multiple copies of the desired VM.
With this option, if you need to make changes to the pool of VMs, you have to do it one by one – changes made on a VM will not be reflected on the cloned VMs. From a manageability perspective, this becomes a hassle. With the lack of a baseline to reference to, whenever the VMs’ configuration deviates away from the baseline, troubleshooting becomes a lot more complex and difficult.
Hence this option of deploying virtual desktops is not commonly used.
Linked Clones are clones of a Virtual Machine that are dependent and linked to a base image for any changes and updates.
The clones share virtual disks with the parent VMs which means they consume less storage than a full VM. This helps to save disk space and allows multiple VMs to use the same software/application installation.
Instant Clones are very similar to Linked Clones. Similarly, they share the parent VM’s virtual disk. However, the main difference is that Instant Clones do the same thing with memory resources.
In a gist, it basically uses the VMFork technology – this allows a running VM to be forked to a child clone. This child clone would share the virtual disk and the memory space with the parent VM, but whenever a new write to the memory or disk occurs, it would store the data into a delta space.
It is because Instant Clones are created based on a running VM instance instead of a powered off one, hence it can be spun up really quickly (usually in a few seconds). They are considered to be more lightweight than Linked Clones and can be fully operational and ready quickly, whenever it needs to be executed. Linked Clones on the other hand, is relatively slower because it requires a full OS boot up.
In general, Instant Clones are the to-go choice for VDI deployment. It significantly reduces time for a desktop to be provisioned and it uses storage resources more efficiently.
Before Horizon 8.0, the Instant Clone technology is only bundled in with the highest edition of Horizon licenses. However, as we recognize that instant clone is a key component in VDI technology because it brings about so many great benefits, we have since removed this commercial limitation and are allowing even our Horizon Standard and Advanced customers to use Instant Clones. This is available to all customers, from version 8.0 onwards.