Few steps one should consider when migrating a legacy application to the cloud or modern multi-tier architecture:
Step 1- Re-evaluate the business model
- Review – redefine the user-customer
- Review – redefine the means by which the user-customer may access the application
- Review – redefine the how are you currently charging for the application and how are you going to charge for the cloud application?
- Review your current cost model, and estimate the cloud cost model
Rule of thumb
- Linux is roughly ½ cost of Windows based instances
- Microsoft Azure offering for Windows instance is cheaper than Amazon AWS offering. However, Amazon discounts their prices with pre-purchase and or 1-3 years commitment; in such case, Amazon pricing would beat Microsoft pricing comfortably.
Step 2- Re-evaluate how the user journey, experience, education, support are affected by the cloud
Step 1& 2 affect the new cloud application design, security framework and Platform selection.
Step 3- Map and identify all components of your current legacy application; most legacy application looks somewhat like this
Step 4- Make the effort; if it is viable; to invest in refactoring the legacy code to look like this
The benefits could be countless and may be a prime factor to your success:
- You mapped the legacy architecture to a potentially very robust cloud architecture
- Your team is the most valuable asset and your legacy team will be highly motivated to take part in the new application. From experience, they are motivated to get their skills adaptable going into the new platform and they feel valuable!
- The legacy application is now mapped to the new platform by separating the business logic and data access from views and forms.
Step-5 Map and design the new data cloud model along with the new cloud application architecture. You will be surprised how the foggy world of the cloud become familiar and how receptive and excited the team will be moving their legacy work to the new Cloud. The list of benefits of doing design the cloud application after accomplishing step 1 -4 are real and tangibles.
This approach could almost be applied to any legacy application even Microsoft Access, Cobol, VB, RDMS single tier Unix or Windows. It will be existing and fun to work on migrating an IBM AS00 or HP3000 applications, I have not worked on one of those for a longtime !!!
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