At the start of this month, Atlantis Computing gave me a preview of their new ILIO Persistent VDI 4.0. As the title of this post suggests, Atlantis have a very nice new feature in this release. Last year, I blogged about their ILIO Diskless VDI for non-persistent desktops which ran purely in memory. That was quite a novel concept, and found affinity with a lot of customers (and won a number of awards too). However, many of their customers asked them to provide an in-memory solution for persistent desktops as well as non-persistent ones. With this release, Atlantis have responded to their customers request and have announced that this ILIO 4.0 release will support persistent desktops in-memory too. To the best of my knowledge, this is the first in-memory storage solution for persistent VDI. The benefits of running your desktop completely in memory are obvious from a performance perspective, but just how do Atlantis do persistent desktops using RAM as the primary storage? Read on to find out – it’s kind of cool.
Atlantis ILIO Persistent VDI 4.0 introduces the concept of a session host, a replication host and a standby host. The session host is where your VDI desktops are running. Using ILIO Fast Replication, changes made to the desktop are sent from the session host over to the replication host. ILIO Fast Replication ensures that the desktop state maintains consistency on persistent back-end storage for fast recovery scenarios. The replication host is responsible for making sure that any changes made to the desktop are saved to a persistent storage device, either SAN or NAS, as shown here.
A best practice would be to keep the session and replication hosts separate. In the event of a session host failure, another host in the cluster can take over the running of these desktops. When the desktop is instantiated on the new session host, the persistent state of the desktop is retrieved by the replication host from persistent storage. The purpose of the standby host is to take over the maintenance of the persistent states of the desktops in the event of a replication host failure. The standby host is also connected to the SAN/NAS storage at the back-end.
Now, although Solid State Disks (SSDs) are shown as an option for shared storage, there is absolutely no requirement to use SSDs. There is just the requirement to store the desktop on persistent storage, and SSDs are an option. And of course the desktops leverage the same excellent set of features that ILIO provides such as Application Analysis, Intelligent I/O Processing, Inline Deduplication and Compression. With all these features in the I/O path, Atlantis estimate that they only need around 3GB of persistent SAN or NAS space per desktop for their ILIO 4.0 Persistent Desktop in-memory solution. It really does seem like a very nice solution.
There is a YouTube video from Atlantis demonstrating the feature here.
This is another great feature from Atlantis Computing which I’m sure will generate a lot of interest in the VDI space.
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