Section 7.2. Server Consolidation and Virtualization Defined

7.2. Server Consolidation and Virtualization Defined

"Our data centers are full!" When we hear our customers say thisand we hear it frequentlywe know that virtualization may provide the optimal environment for them to consolidate their servers. But what do we mean by consolidation? In general terms, consolidation means joining multiple entities together into a single entity. For example, merging multiple remote data centers into a single location, streamlining the amount of space used within a single data center location, eliminating multiple overlapping or redundant applications into a single unified application, or reducing multiple physical servers into a single physical server that supports multiple virtual servers. The last of these examples serves as our primary focus: reducing the number of hardware server platforms in your environment.

Consolidation has many benefits, including better utilization of company assets, better control of resources, and the overall reduction of hardware capital costs. Specifically, server consolidation has positive ripple effects on other types of consolidation. For example, reducing the number of physical servers results in reduced requirements for floor and rack space, power consumption, air conditioning, and data wiring. This allows a given data center to reclaim physical space. Or consider an entire data center consolidation. If the servers are virtualized before decommissioning the remote data center, the server hardware can be re-tasked, sold, or otherwise disposed of locally, thereby saving the cost of shipping. Additionally, server consolidation can provide a cost-effective alternative to data center expansion or relocation.

Consolidating the number of physical servers also reduces the hardware required to operate a service or group of applications. This, in turn, reduces the operational costs of maintaining this hardware, which can contribute to improving the overall quality of the service. The organization as a whole benefits from standardization of operating systems, better utilization of systems resources, a reduction in physical space needed to contain the servers, easier manageability, and an increase in security. The net result is a more proactive environment, and more time available to focus on providing value back to the business.

Now that we've defined consolidation, let's narrow our focus to virtualization. As with consolidation, there are several forms of virtualization such as storage virtualization, server virtualization, and application virtualization. We have all witnessed the rapid adoption of SANs (storage area networks), the practical implementation of storage virtualization. Storage virtualization basically took the direct attached (unshared) storage devices and created a generally available, shared storage device. A greater amount of storage becomes available in a shared environment, making it easier and more cost-effective to manage.

Server virtualization does for server hardware what storage virtualization did for disks: it makes the server hardware a generally available, shared hardware platform. By server virtualization, we mean the logical partitioning of a single hardware platform into multiple virtual hardware platforms through a software layer. Simply put, virtualization software allows you to run many operating systems on a single hardware platform. This is what VMware's ESX Server does: it abstracts the server hardware from the operating systems that run on it. VMware pioneered x86 server virtualization software, and its stability has brought the use of virtualization to the production-distributed systems environment. Building upon server virtualization, we are now seeing application virtualization: that is, encapsulating individual applications to run in their own isolated environment, one that isn't tied to a physical server platform.

For the purposes of this chapter, when we refer to virtualization we are focusing on server virtualization, which enables physical hardware consolidation. It's important to note that even with server virtualization you still need to purchase the individual server operating systems and third-party software agents that you plan to run in each virtual machine. So it's still important to achieve results in the area of server consolidation by stacking multiple applications on one virtual machine and running multiple virtual machines on one physical server.

7.2.1. Adoption and Support of Server Virtualization

Sounds great, but is it industry-proven and do vendors support it? This is one of the first questions an organization wisely asks about any new technology. As we have already mentioned, mainframe-based virtualization has been well established for decades. UNIX- and AIX-based virtualization is somewhat newer but also accepted and deployed. Windows/Intel-based virtualization is the next logical step. Many organizations have recognized the significant cost and complexity savings made possible by server consolidation and virtualization software, not only in their test and development environments but in production as well.

Regardless of the adoption rates and unique ways customers are currently using server virtualization, the next question is whether VMs are supported by software vendors. The answer is yes. Enterprise customers are finding that the proliferation in the number of smaller servers has resulted in very low utilization of server resources. How underutilized are large server environments today? At one of our customers, Callisma found an average utilization of 4 percent across 3,000 servers. This vast underutilization represents a significant cost to the business with no benefit. Consequently, customers like this one are driving operating systems, applications and hardware vendors to support virtual machines, and the vendors are responding. For example, in a recent announcement, Microsoft detailed a wide range of support options for customers utilizing VMware. The following URL provides more detail: www.vmware.com/pdf/ms_support_statement.pdf.

Increasingly, our customers are finding that both server consolidation and virtualization software are viable in a Windows server environment. More than that, these technologies are necessary to reduce the volume of systems required to deliver a given service. The experience of our customers reflects the wider trend of industry adoption and support of virtual machines by software vendors.