Shopping for Server Virtualization?

The big players in the server virtualization market each offer advantages, although a few of the tools are only for Windows.

VMware

Market leader VMware offers an excellent line of virtualation products. However, VMware's VirtualCenter management tool, which plays the role of managing the guests on the ESX and GSX servers, only runs on Windows at present – and it doesn't look like a Linux port will be on the roadmap any time in the near future.

If you prefer a Linux-only solution, you have to make do with the free VMware server. This entry-level solution still has much to offer. The biggest visual change compared with the previous 1.x version on VMware server is the new web interface, Virtual Infrastructure Web Access. (The former standalone server console is no longer usable.) This web interface requires a separate browser plugin (Figure 1).

Figure 1: OpenQRM lets you manage physical and virtual computers with a single tool.

Provisioning and deployment of VMs is supported by a large number of templates – for 17 Windows versions and 17 Linux distributions (including 64-bit variants) – as well as NetWare and Solaris 10. Although VMware Server does not let you migrate VMs between physical machines (in contrast to its big brother ESX Server), and definitely not at run time, at least virtual machines can reside in a shared memory area exported by NFS. Load balancing is also restricted to the commercial versions; however, the free version has excellent centralized server administration and monitoring.

Virtual Iron

Virtual Iron is hot on the heels of VMware. Its Virtual Iron 4 product, or at least the most expensive Extended Enterprise Edition, not only supports cloning of virtual instances and live migration, but also dynamic capacity management of virtual machines at run time.

The Virtual Iron virtualization environment also includes high-availability features, such as failover for virtual machines on a reserve host (N+1 clusters). Virtual Iron comes with sophisticated monitoring and logging for virtual instances and policy-based capacity management, which gives administrators the ability to swap out virtual machines automatically if a host exceeds a specific load threshold.

On the storage side, Virtual Iron supports iSCSI, SAN (Fibre Channel), and NAS. VMware's lead on its competitors is no longer very substantial; however, the price differences are still significant. Virtual Iron starts at US$ 500 per socket, whereas the price for VMware's ESX Server starts at approximately three times that.