In any Data Center Migration project, it is recommended to minimize application changes and move application and associated servers & data in move groups. The strategy is important, so that enterprise business application don’t break during migration.
The migration strategy should be based on simple guiding principles for executing a server migration, which are:
· Application architecture will remain unchanged from current state to future state
· Impacts to the business will be minimized through thorough testing prior to cutover and detailed business contingency planning
· Acceptable application response time will be verified through performance testing as needed
Application categorization should be conducted in order to give a preliminary assessment of the effort and risk involved in moving applications. It should be used to help identify which applications require greater concentration during the further planning and design phases of the data center consolidation / migration program. Application categories serve also as an important input for preliminary estimation of migration timeline.
Business criticality reflects the importance of a given application to the business and the possible impact if the system is not available. On the other hand, move complexity indicates both the duration of effort and the risk associated with managing complexity. Together, they assist to assess an average cost for each category that incorporates time, effort and risk.
• Mission Critical (absolutely no downtime)
• Business Critical (some downtime in hours)
• Essential & rest of the applications (can be offline for a while)
• Simple to move
• Medium – more difficult to move
• Complex to move
Application Classification Strategy
– Simple, Medium, Complex
– Assign each app to a cluster. Ie identify lcd of applications that must be moved at same time
– Shared DB, or OS, Closely Integrated apps, Shared H/W,
– Indentifying clusters that must be moved at the same time
– Single LOB, resource logistics,
– The order in which groups will be moved
– Simple to complex
Move group or Wave Strategy should be developed which sequences applications into
Move Group or Sequence of move is determined by:
Level of complexity, application dependency, risk mitigation, and manageable components of work
1. Standalone / Low complexity application should be prioritized to lead the wave deployment in order to shake out new infrastructure and process, decreasing the overall risk of migration.
2. Dependent applications followed the standalone applications with most complex assigned to last wave of deployment
3. The development, test and Pre-Prod environments should be migrated before the production environments to further mitigate the risks associated with the migration.
Review against Technology Architecture for compliance with existing architecture and standards
Application Team’s consensus/recommendation for Host to VM Migration Strategy
The core infrastructure should lead all deployments as all servers depend on this
In any particular move group applications should be grouped together to minimize the
Migration schedule taking into consideration the above principles.