The clever techies behind Sun Microsystems' VirtualBox hypervisor just keep plugging away on improving the product, as if the $7.4bn Oracle acquisition had not happened and as if Oracle will have anything useful to do with VirtualBox other than sit on it and keep it out of a rival's hands when the deal gets approved by the European Union's antitrust regulators.
Considering that VirtualBox came from a German company (Innotek) that Sun bought in February 2008 because its own Xen-based virtualization efforts were woefully behind, one could make an argument that just like Oracle getting its mitts on MySQL will thwart competition in the database market, Oracle taking control of Sun and therefore VirtualBox will also reduce competition in virtualization - and probably mean the end of the line for one of Sun's most popular programs.
(If popularity is measured by downloads, not money, as it certainly is with MySQL: VirtualBox has had 20 million downloads in the past two years, and is getting around 40,000 downloads a day.)
The irony, of course, is that with the release of VirtualBox 3.1 today, Sun's type 2 (or hosted) hypervisor is ready to play with the big boys even though the product is not a type 1 (or bare-metal) hypervisor. The ability to migrate live virtual machines around a network of PCs or servers is the killer feature that is driving a lot of server virtualization these days after an initial wave of virtualization-enabled consolidation of workloads.
Allowing for server and PC images to be teleported around physical machines, thereby allowing for maintenance of physical iron without shutting off applications and allowing for high availability failover of VMs, is something all companies need to be thinking about doing. Certainly for their servers and probably for their PCs.
According to the release notes and the updated manual for VirtualBox 3.1, this is what Sun is calling major release, and the live migration feature is the big change from the 3.0.8 release that was kicked out in mid-October.
This live migration can occur on any x86 or x64 machine, regardless of the underlying host operating system (which can be Solaris, Linux, or Windows) so long as there is some sort of TCP/IP link between the two boxes and they have access to the same iSCSI network storage array (accessible through NFS or Samba/CIFS).
For teleportation to work, you have to configure a virtual machine on a target box with the same basic virtual hardware settings as on the source box (memory, virtual processors, and so one), making sure the source and target boxes have "fairly similar CPUs," meaning you can't have Athlon or Opteron processors in one box and Core or Xeon chips in the other box unless you like error messages.
This is the same starting place where VMware's ESX Server and the open source Xen hypervisor was with live migration, although some hypervisors now allow for live migration between machines that just have local storage or different network storage so long as they have a network link.
VirtalBox 3.1 has a number of other tweaks. Sun says that optimizations in the memory handling parts of the hypervisor have improved its performance by 30 per cent over the prior release. The hypervisor has "significant performance improvements" for PAE and AMD64 guests using VT-x and AMD-V virtualization features. PAE is short for physical address extension, and it allows a hypervisor running on a 32-bit machine to address memory beyond 4GB and up to 64GB.
The network portions of the hypervisors have been buffed and polished too, delivering higher network throughput and gobbling up fewer CPU cycles. The 3.1 release also allows you to change the network attachment type in a running VM, which would have caused much consternation before. The update also has support for paravirtualized network adapters, support for reaching into Windows hosts and using its native drivers to do the video on guest VMs (thereby giving native performance), and the ability to restore a VM from an arbitrary snapshot instead of the last snapshot done by a user.
You can download VirtualBox 3.1 here. Sun charges $30 per year per machine for 24x7 technical support on a PC and $500 per year for every four sockets on a physical server. ®