We have 7 BO 5.x/6.x Repositories (Contain 20 Applications)
Have to migrate all applications into BO XI.
For this we have to prepare Scalable and Failover BO XI Architecture.
Anyone please help me to prepare a BO XI Architecture? Means Pre-Requistes and methodology.
mannemn 
(BOB member since 2007-06-28)
I suggest you to hire a consultant or consultants who have done it before. It is not something we can explain to you in a few sentences and you can magically have it done. it is a very involved process and it requires a lot of expertise.
Business Objects Global Services have tons of experiences. And many of the BOBers here are well-qualified for the task.
substring 
(BOB member since 2004-01-16)
Here is some useful info on the XI R2 architecture
https://bobj-board.org/t/86530
EnterpriseArchitect (BOB member since 2006-03-23)
I agree with substring. Specially since you have 7 repositories and you want to implement the scalable and failover architecture, it is always advisable to hire a consultant who has experience with it.
Kashif Saeed 
(BOB member since 2004-06-02)