Open source hypervisors may be free, but full, enterprise-class open source virtualization software comes at a price.
Red Hat, Citrix Systems, Novell and Oracle offer open source virtualization software for the enterprise, and all four charge for support, advanced features and management. This article breaks down the costs of these four open source virtualization options to help you find the best fit for your infrastructure.
Red Hat Enterprise Virtualization is based on the Kernel-based Virtual Machine (KVM) hypervisor, while the others are Xen-based. The source codes for KVM and Xen are free and publicly available, but advanced features (such as high availability) and a decent management interface require additional purchases. In addition, Oracle, Novell and Red Hat offer subscription-based software, which comes with a yearly fee.
But depending on which features you want to use, you should consider all four open source virtualization software options and weigh the costs.
Red Hat Enterprise Virtualization
Red Hat's enterprise-class version of Red Hat Enterprise Linux (RHEL), called RHEL Advanced Server, offers everything you need to run a virtual infrastructure, including high availability and the Global File System, a shared-disk cluster file system. Version 5.5 also includes Conga, a Web-based management platform for virtual infrastructures. Red Hat lists RHEL Advanced Platform at $1,499 per physical server per year.
For open source virtualization in the enterprise, Red Hat also offers RHEV as a separate product. This enterprise-ready open source virtualization software is available as a starter kit for $2,994. You can run RHEV on six sockets, which for most environments means three hosts. RHEV comes with high availability, an automatic load balancer and a power-down option for physical servers when they aren't needed. While RHEL Advanced Server does include a virtualization stack, RHEV is meant for fully virtual environments. So, RHEL is fine for an organization that simply wants to run a few VMs, but RHEV is the better option for companies that want a full virtualization solution with an easy-to-use management platform.
Citrix XenServer, based on the Xen hypervisor, comes in no less than four different versions: XenServer Free, XenServer Advanced ($1,000 per node), XenServer Enterprise ($2,500) and XenServer Platinum ($5,000). If you're interested in a XenServer version that at least offers clustering and a decent management platform, you'll need XenServer Advanced. The Enterprise and Platinum editions are more focused on virtual workload automation.
When it comes to open source virtualization software pricing, Oracle is clear: Oracle VM is free. Oracle Enterprise Linux, the underlying platform needed to run Oracle VM with full support, is also free. But in an enterprise environment, you need to have support as well, and that's where pricing becomes less clear.
Let's start with Oracle Enterprise Linux. Support for the product is divided in two. Network support costs $107.10 annually, which includes access to patches and other useful online resources. In addition, the price for technical support is $449. Considering that the minimal support you need in an enterprise environment includes at least some life support from a human being, the minimal support price for Oracle Enterprise Linux comes to $556.10 per node. But you also have to pay for Oracle VM support. This costs $539.10 for virtual machines (VMs) with a maximum of two physical CPUs. Ultimately, support costs for Oracle VM and its platform bring this open source virtualization solution to a total of $1,092.20 per node.
Novell SUSE Linux Enterprise Server
Red Hat, Citrix and Oracle offer one important element that Novell does not: a decent management interface. Novell's Xen-based SUSE Linux Enterprise Server (SLES) includes only the basic virt-manager tool. Many Novell customers use PlateSpin to manage virtual environments, but PlateSpin doesn't use open source virtualization technology. If you want to add high availability, you can add the crm_gui, which comes as the default management tool for the Pacemaker High Availability solution.
As far as pricing goes, Novell is more or less in the same range as the others. Novell uses the same model as Oracle: The software by itself is free, but you pay for support and updates through a yearly subscription. The cheapest subscription for SLES will cost you $349 per node, with no limitations on the amount of CPUs or VMs that you can run. The only feature that requires a separate purchase is the High Availability Extension, which is $699 per server per year. This brings the grand total for Novell open source virtualization to $1,048 per year. But for a similar price, you can get more complete solutions, more advanced features and better management interfaces with the other three vendors.
Open source virtualization cost considerations
If you want the benefits of high availability, an easy-to-use management tool and all other virtualization management features, Red Hat Enterprise Virtualization offers it all for $2,994. If you don't need every feature of RHEV or if you prefer Xen over KVM virtualization, Citrix comes close with XenServer Advanced. Other open source virtualization offerings are just not as complete for the same price.
Sander van Vugt is an independent trainer and consultant based in the Netherlands. Van Vugt is an expert in Linux high availability, virtualization and performance and has completed several projects that implement all three. He is also the writer of various Linux-related books, such as Beginning the Linux Command Line, Beginning Ubuntu Server Administration and Pro Ubuntu Server Administration.