Now that Server Virtualization is mainstream, maximizing your benefits and scaling your virtual infrastructure is increasingly important. Virtualization affects not only technical aspects of your environment but organizations should consider the people and process component to ensure a mature virtual infrastructure is deployed. When embarking on server virtualization deployments, enterprises should consider the following ten best practices to help achieve successful results.

1. Define Your Virtualization Strategy
Establishing consensus for your virtualization strategy can be challenging. Virtualization provides a shared infrastructure that delivers greater economies and efficiencies. But business units are accustomed to “owning” physical servers, keeping their applications and data physically delineated from others business. Utilizing a well-documented business case will drive adoption of virtualization. Breaking the entrenched habits of decentralized procurement, provisioning and management will take willpower, executive commitment and clear support from the CFO as appropriate.

2. Understand Consolidation Ratio Implications
Virtualization reduces the number of physical servers in your environment by consolidating a number of virtual machines (VMs) on a single physical server. This consolidation ratio introduces considerations, such as disaster recovery, that must be taken into account as you design and deploy your virtual infrastructure. Before virtualization, the typical consolidation ratios for application stacking were 2-1 to 4-1. With this low ratio, the impact of the physical server going down is minimal. If your consolidation ratio is 20:1 or higher, the impact on the enterprise will be greater. Typically 65-75% utilization of your hosts is a good target.

3. Assess the Physical Environment
The physical assessment is a critical precursor to an accurate virtual infrastructure design, which needs to meet business and technical requirements. This should include server utilization statistics, network topology and requirements, access to storage such as SAN and NAS, power and cooling considerations, rack and space availability and disaster recovery implications.

4. First Optimize, Then Virtualize
Don’t consider each application an automatic candidate for virtualization. Review the application portfolio to consider whether any applications can be sunset early. Just because a server may have low usage statistics that does not automatically make it a candidate for virtualization. Some applications should be sunset due to lack of need, replacement with newer applications or lack of support.

5. Validate Application Supportability
As you consider migration of physical servers into your virtual infrastructure, ensure the applications being migrated and their operating systems are supported. Check with your application vendors to ensure they will support a virtualized topology of their applications under the support contract currently in place.

6. Be Prepared to Invest in Your Human Resources
Human resource factors are often overlooked in virtualization projects. Virtualization technology is conceptually simple, but requires high-demand skills to plan, design, integrate and maintain. You may need to enhance your in-house skill set. Linux, storage, inter-networking and disaster recovery skills may not be enough. A professional services organization with virtualization expertise may be needed to design and manage the solution.

7. Make Sure the SAN and NAS are in the Plan
Although you can deploy a virtual infrastructure onto local storage, to fully utilize the flexibility of a virtual infrastructure, a shared storage environment, such as a SAN or NAS, is required. As your virtual machines will be on this shared storage, it is critical you have a well-defined storage provisioning and management process.

8. Anticipate the Management and Security Requirements
Management is critical to avoid virtual machine (VM) sprawl or inadvertent host interruption and ensure timely response to application/VM issues. Management processes need to be clearly defined and documented as the virtual infrastructure is rolled out into production.

Security requirements should also be a primary consideration. Limiting root access to the service console and controlling root passwords is critical as the root can control all virtual machines on a host, thus introducing instability and an inability to track changes. Adding Active Directory authentication onto your virtual infrastructure will allow for stricter password and account policies to be maintained.

Limiting access to management cards is recommended as the ability to reboot or shutdown physical servers could cause a power down or failover condition on your virtual machines.

9. Document Your Physical to Virtual (P2V) Migration Plan
Your P2V migration strategy should minimally change the physical server you are migrating. Optimize the plan for consolidation onto target systems and group applications with similar maintenance windows so downtime on one application does not impair the service levels of other applications. Applications with similar peak usage periods, such as end-of-month processing, may not co-exist well on the same physical machine.

10. Take a Phased Approach
A phased approach for your migration allows you to move thoughtfully and mitigate problems as they arise. It will help you determine ideal candidates for virtualization, and adjust your migration strategy. The more you conduct migrations, the better you will be with them.

Virtualization projects are not just technical initiatives. People and processes should be considered to help ensure that the virtual infrastructure is scalable and produces the desired results. Even if you have already deployed a virtual infrastructure it can behoove enterprises to engage professional services firms to optimize the people and process components to ensure a scalable and mature virtual environment.

To view this paper in its entirety, visit www.business.att.com/enterprise/exchange_resource/Topic/managing-technology-change/Article/10_best_practices_for_server_virtualization_planning

For more information on virtualization, visit “Trends” on AT&T’s Networking Exchange at www.business.att.com/enterprise/exchange_category/Topic/technology-trends/ and also visit www.att.com/hosting.
AT&T Consulting