Cognos server sizing

Hi Guys,

Does anyone know how to decide how much memory server requires depending on user load.How to determine statistics and all that stuff.Its very important considering your server needs to be up all the time and also deciding what is the backup plan.

Considering you are asked to plan a cognos architecture from start.How would you do it.You need to give specs for a server, backup server and that server should hold the current users and you need to keep in mind that additional users are going to be added.

1)availability
2)capacity
3)scalability.

You need to keep all this in mind.While planning so depends how you do it.I am working on this architecture and deployement guide is the place to start it.