Virtualization is simply software emulation of hardware resources such that one physical machine can effectively function as several logical discrete machines. Since this abstraction is done at machine level, it's often referred to as platform virtualization. This concept has further been extended to virtualize specific system resources such as storage volumes, name spaces, and network resources and is commonly called resource virtualization. While this book will discuss both kinds of virtualization at various points, it is nonetheless primarily platform virtualization that is the central theme of this book. Thus, generic references to virtualization will always mean platform virtualization.

There are five kinds of platform virtualization technologies and products as highlighted below by Figure 1.

This book will restrict itself to the first three platform virtualization technologies: Hard Partitions, Para-Virtualization and Full or Native Virtualization.

VMware Server and Microsoft Virtual PC are probably the best examples of Full (or Native) Virtualization and both products are free. As you move up the virtualization technology ?food-chain?, the products become increasingly expensive. VMware Workstation offers just a few more features than VMware Server and it costs about $170. Para-Virtualization products like VMware ESX range in price from $1000 to almost $6000 per two processors (Note that Sun's Logical Domains are free). Moreover, the Hard Partition Virtualization products? prices tend to be based on the hardware configuration (i.e. # CPU's) and neither the hardware nor the virtualization software in these enterprise class machines tends to be cheap.

Virtualization's Popularity

The meteoric rise in popularity of virtualization is nearly unheralded. In 2006, Gartner listed five of its top ten strategic technologies for 2007 to involve virtualization. Such preponderance in one category has never before or since occurred in their annual technology survey. Few information technologies have grown so quickly or had as optimistic a market potential as virtualization as shown below in Figure 2 by IDC's ?Rise of Virtualization? projections.

If the virtualization market growing 350% in just five years is not astounding enough, then look at VMware's 2007 stock chart shown below in Figure 3. In just three months, this stock rose from its IPO price of $29 to over $104 - an amazing 260% growth in just three months! That's an astounding stock chart in the post tech-bubble bust. But virtualization is just that hot - and clearly here to stay.

Virtualization's Benefits

There are so many universally acknowledged benefits attributed to server virtualization that it is reasonably unnecessary to provide a complete and comprehensive list in this book. But let's examine some of the more relevant advantages, especially as it potentially relates to Oracle databases.

• Lower IT Infrastructure Costs

• Improved Resource Utilization

• Greater Server Consolidation

• Enhanced High Availability

• Faster Disaster Recovery

• Using Virtual Appliances

• Better & Faster Provisioning

• Lower Power & Cooling Costs

• Reduce Server Room Space Needs

• Hardware and Image Independence

Do some of these points sound familiar? Maybe that's because Oracle's been working on improving along several of these criteria with their newer database technologies, such as RAC and Grid. Plus, Oracle's extensive platform support and features like cross-platform transportable tablespaces clearly target hardware independence. What that means is that both virtualization and Oracle's technology trends are quite harmonious. They are very clearly not at odds.

So as system architects and database administrators, we should look for opportunities for these various technology solutions to augment, compliment or supplant each other. And that's not a bad thing. It simply means that some problems and their solutions are best handled at various levels and not always within a specific technology such as within the database itself. For example, which scenario offers simpler new database deployment and provisioning?

Traditional Method
Operating System
Install
Patch
Optimize


Database Software
Install
Patch
Optimize
Database Itself
Optimize init.ora or SP-File settings
Create Database
Define Initial -
Disk Groups & Tablespaces
Roles, Profiles, Policies & Resources
Schemas, Tables, Indexes, Views, Code, etc
Jobs, Programs, Classes, Schedules & Chains
Grants, Contexts, Pub/Priv Synonyms & Links

Via Virtualization
Deploy Database Virtual Appliance

This is an excerpt from Oracle on VMWare: Expert tips for database virtualization by Rampant TechPress.