Top Ten Server Virtualization Technologies to Consider

Server Virtualization Technologies:

The playing field for server virtualization has become much more crowded over the last few years. Competition is always good for a market as more choices always push vendors into providing better products at more competitive prices. It can be very time consuming to digest each vendor's marketing materials to come to the right solution for your organization. This checklist provides a list of the main considerations and basic differences between the server virtualization technologies to provide a starting point for technology evaluation. The three main technologies discussed in this analysis are: hardware virtualization, para-virtualization and OS virtualization.

Sever Virtualization Technology Overview

HARDWARE SERVER VIRTUALIZATION TECHNOLOGIES
Hardware virtualization is probably the most commonly known server virtualization technology, including products from VMware, Parallels and Microsoft. The technologies are designed to support multiple types of OSs on a single server and are characterized by technology that virtualizes hardware resources in order to manage and dedicate them to Virtual Machines on the server.

PARA-VIRTUALIZATION

Para-virtualization is similar to hardware emulation because in concept it is designed to support multiple OSs on a single server. The only implementation of this server virtualization technology today is the Xen open source project. Xen customizes the operating system to provide more efficient processing and lower overhead which results in better performance than hardware emulation.

OS SERVER VIRTUALIZATION TECHNOLGIES

OS virtualization is a third approach to server virtualization technology and has been implemented by SWsoft's Virtuozzo and Sun's Solaris Containers. The concept is based on a single OS instance, which provides a leaner more efficient architecture and a single OS per server for management and updates. The main limitation is that it does not support multiple OSs on the same server so it is intended for organizations that are consolidating or deploying multiple virtual servers on a single Linux, Windows or Sun physical server; Solaris Containers obviously supports Solaris while Virtuozzo supports both Linux and Windows. SWsoft Virtuozzo for Linux product does support multiple Linux distributions in the guest virtual servers.

Ten Considerations

#1. MANAGEMENT TOOLS

Many organizations undertake virtualization projects because they can quantify the hard costs of hardware sitting in data centers at 15-20% utilization rates. While hardware and environmental costs are considerable, the administrative costs for managing servers are the largest cost component. Administrative tasks include OS and application updates and patches, backups, installations and provisioning.

The management tools available for each solution vary widely. Some solutions have very few tools available and may be extremely limited. There are many excellent toolsets available with the more mature products.

The process of moving a physical server to a virtual server can be daunting task, particularly if the server is critical to the business. Most of the vendors have tools that help in the migration process, and there are some external vendors that have provided tools for moving not only from physical to virtual, but between virtual environments and even from virtual back to physical. The ability to evaluate a physical server for resource utilization trends to predict and configure an adequate virtual server is rated as the most important component for physical to virtual transition, even above the simple requirement of moving data reliably to a virtualized server. The resource trending capability is only available in a few select P2V tools.

#2. VIRTUALIZATION LEVEL

Para-virtual and hardware virtualization solutions virtualize the technology from the hardware up to the OS. OS virtualization sits on top of the OS, virtualizing a single instance on a server and taking advantage of all of the underlying hardware technology. Hardware virtualization looks exactly like a dedicated server, ten servers consolidated onto one will still have ten plus one underlying OS.

OS virtualization requires only a single OS instance, although in certain cases OS variances are supported. With the ease of deploying virtualized servers, hardware virtualization sites have actually seen an increase in the number of virtualized servers, beyond what would have been approved on a single server basis. With the complete OS and application structure of each virtualized server, the management workload for IT teams has gotten even larger, rather than decreased with these types of virtualization solutions. OS virtualization deploys on a single OS per server, limiting it to a single OS type, but in the case of management this is quite beneficial.