The economics of consolidating large numbers of poorly utilized servers under VMware or other virtual server products is a no-brainer. Projects usually break even within a year, provisioning of new virtual servers is improved from weeks or months to hours, and if storage virtualization is tackled as well, overall computing and power costs can be significantly reduced.
Clearly the first application areas that have been virtualized are the less mission-critical. File and print servers, data mart servers, development and networking servers, and tier 3/tier 4 applications have been moved across in droves.
However, IT departments have correctly been holding back on moving tier 1 and tier 2 mission-critical applications. Reasons include a natural lag and reluctance to change anything in a mission critical environment that works. But other factors impact the business decision to virtualize workloads:
- Mission critical applications (especially high-performance applications), tend to have higher processor utilizations, so the business case for migration is not as strong;
- VMware's processor performance overheads become more acute in mission critical workloads;
- I/O performance and manageability issues in virtualized environments can impact the achievement of consistent response times and data availability levels;
- Elapsed time for application support services such as backup, recovery, and business continuance processes can be significantly longer, which can impact meeting RPO and RTO service levels for the applications.
EMC’s VMware group is working with Intel and other partners to introduce improved architectural features, and has aggressive plans to introduce additional end-to-end capabilities for a virtualized infrastructure. However, this will take time and requires significant testing by the industry as a whole and specific data centers before they reach general acceptance. In the meantime, IT organizations should and will work their way up the application tiers one at a time, introducing pragmatic virtualization infrastructures according to the business requirements of the applications.
Action Item: Most organizations will keep some application groups off virtual environments for the foreseeable future. IT executives should not force-fit all application groups to one virtualization environment. It is likely that multiple virtual environments will be created to meet the performance, availability, and recovery requirements of different application tiers. Senior IT executives should be careful not to oversell the adoption and cost reduction potential of virtualization for mission critical applications.