In respect to what KPI your organization follows or not, The simplest way for IT architect (matters any Architect) to measure his/her success is:
1) Develop your growth plan for short term and long term, what and where you want to be.
2) Knowledge Acquisition in changing business demands.
3) Build a design or solutions were all business elements (People process and Technology) are met and bridge all the gaps.
4) Achieve excellency in your work to gain buy-in for all your plans and designs.
5) Request Testimonial/Recommendations for your work (efforts are useless if you're not appreciated).
If you are done with above, you are on TOP success list, rest will follow :)