INFO 2004 Chap.5 Cloud Migration: The Six Rs
Cloud Migration: The Six Rs
Migration strategy is the intellectual spine of the three-stage Cloud Migration Plan strand. The course first names Gartner's earlier five—Rehost, Refactor, Revise, Rebuild and Replace—then distinguishes the six commonly used strategies: re-host, re-platform, re-factor or re-architect, re-purchase, retire and retain.
Several carry memorable colloquial labels: re-host is lift and shift, re-platform is lift, tinker and shift, and retain is re-visit. Do not merge the historical and current lists. The source also supplies an increasing-complexity ordering: retire, retain, rehost, repurchase, replatform, refactor or rearchitect. That order is a starting point for reasoning, not a recommendation by itself.
Selection still depends on the organisation, the workload, the change sought and the acceptable migration effort.
What this chapter covers
- 01
Gartner's distinct five-strategy history
- 02
The six current migration strategies
- 03
Re-host as lift and shift
- 04
Re-platform as lift, tinker and shift
- 05
Re-factor or re-architect as deeper change
- 06
Re-purchase, retire and retain
- 07
Increasing complexity and scenario selection
Choose a strategy and defeat the nearest alternative
- 1Eliminate retire because the workload remains needed and retain because a move is required.
- 1Treat re-purchase as a product change and re-factor as a deeper redesign; neither matches the limited-change goal.
- 1Compare re-host with re-platform. Re-host best matches speed and minimal change; re-platform would introduce selected adjustments.
- 1State the trade-off: choosing the lower-change path defers some improvement and should be reviewed later.
Key terms
- Re-host
- Move a workload with little change; commonly called lift and shift.
- Re-platform
- Make selected adjustments while moving; commonly called lift, tinker and shift.
- Re-factor or re-architect
- Change the application more deeply to suit a new architecture.
- Re-purchase
- Move to a replacement product rather than migrate the existing workload unchanged.
- Retire
- Remove a workload that is no longer required.
- Retain
- Keep a workload in place and revisit the decision later.
- Migration complexity
- The course orders the strategies from retire through retain, rehost, repurchase, replatform to refactor or rearchitect as complexity increases.
Cloud Migration: The Six Rs FAQ
What are the six Rs?
Re-host, re-platform, re-factor or re-architect, re-purchase, retire and retain.
What were Gartner's original five?
Rehost, Refactor, Revise, Rebuild and Replace. They are a distinct historical list.
Which strategy is most complex in the course ordering?
Refactor or rearchitect appears at the high-complexity end; retire appears at the low end.
Is the lowest-complexity option always best?
No. Complexity is one criterion. Business purpose, workload condition and desired change still determine fit.
Assessment move
Memorise the two lists in separate boxes so their overlapping names do not blur. Then practise a six-way elimination method: needed or not, move now or later, keep or replace the product, preserve or change the application, and how much complexity is justified. Close every practice answer by naming the nearest rejected strategy and the criterion that defeats it.
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