Gosh, it’s three and a half years since Xen 3.0 first shipped.  Time flies when you’re having fun.  Xen.org has announced the availability of Xen 3.4, which offers the community the results of a couple of major evolutions of the Xen code base and its community, as it has become a major player in the industry (I’ve seen IDC and Yankee surveys that validate that Xen is used for ~20% of virtualized server sockets today, with an accuracy of +- 3%.  It’s going to be an exciting year…  Anyway, back to Xen 3.4.  Here are some major categories:

-          Xen Client Initiative (XCI) - Xen 3.4 contains a first release of the Xen client hypervisor to offer the community a compact client hypervisor with tons of features for testing and further development.  For the first time the Xen project is moving away from providing simply the hypervisor, and leaving it to vendors/users/developers to build their own system.  This release contains the whole enchilada, including Dom0, the management tool stack and Xen.  In other words, everything you need to be up and running with a Xen client system.

-          Reliability – Availability – Serviceability (RAS) – From a server-side perspective, Xen 3.4 has a raft of new  features to avoid and detect system failures, provide maximum uptime by isolating system faults, and provide system failure notices to administrators to properly service the hardware/software. The combinations of these services provide for a robust Xen hypervisor with fault-tolerant and back-up capabilities built-in.

-          Power Management – Xen 3.4 substantially improves the power saving features with a host of new algorithms to better manage the processor including schedulers and timers optimized for peak power savings.  Many of these changes are applicable to both client and server machines, but for example one of the features that I like on the client side scheduler is an ability to synchronize clock ticks to VMs for which the timer frequency is known, to maximize  CPU idle time and maximally utilize CPU awake time.  This is good for battery life on client systems where in general users are up for disappointment when they realize that more VMs (read: more security/flexibility) can easily translate into worse battery life.  This is the key reason that I decided to ditch a type-2 client side product recently, because my Mac battery wouldn’t make it through a flight.

You can find the bits at the Xen.org website at: http://www.xen.org/download