As you’ve probably heard, today is the day the game changes for server virtualization, with Citrix offering XenServer for free and introducing advanced management for both XenServer and Hyper-V in the form of Citrix Essentials.

One question I’ve been asked has been: how did we determine what should be in the free virtualization platform?

Simple. We start with this proposition: XenServer = not just a free hypervisor, but the basic management capabilities 100% of or users require to make use of it in production,  pre-production, and production support scenarios. Citrix Essentials = the advanced management capabilities that add value to advanced scenarios -- mainly business-critical production, but also high-end production support and pre-production scenarios.

(By “pre-production” I mean development, test and staging.  By “production support” I mean technical support, demo, and training.)

We survey users of our products to find out why they bought the edition they bought, and what they’d like to see that is available in higher-end editions, among other things.

100% of Enterprise Edition users said they bought that version instead of the dearly departed Standard Edition because of XenMotion live migration, resource pools with shared storage,  and centralized multi-server management. 100% of Standard Edition users said those were the features they would like to be able to add.

So we put them into the new free XenServer, because they are the baseline of management that 100% of our users are looking for.

As we go down the list, percentages fall off a bit of a cliff.  The next most-requested feature is high availability, at about 30-40%. Despite others’ best efforts at promotion, only a few companies implement high availability on 100% of their virtualized servers, and of those, far fewer protect all workloads.  So we included high availability for XenServer in Citrix Essentials, Enterprise Edition -- so the 30-40% of customers who want availability protection for their 10% or 20% (or more) of their workloads they consider business-critical can pay for the ability only on the servers they want to protect -- and run the majority of their workloads on the new free XenServer.

Similarly, our advanced StorageLink technology -- currently offered for NetApp and Dell EqualLogic storage, but delivering deep integrated management for more storage in a near-future release. Basic storage integration with logical volume management and VHD support for everyone – advanced StorageLink technologies for Citrix Essentials users.

So: if every user needs it to go beyond free hypervisors to a free virtualization platform that every server needs -- it’s in the new free XenServer.  If it adds value to specific server roles, hardware, or other integrations -- it’s in Citrix Essentials.  It’s that simple.

(Apologies to John Irving and Nicholas Meyer for the titles.  The original versions come from books that are well worth a read.)