How to calculate servers for an RDS farm?

Question

Scalability

Good day to all!
Please help me to solve this problem, description below.
Given:
1000 users,
assumes using RemoteApp on Windows 2008R2,
1-2 applications per user, totaling about 200 MB of RAM by Task Manager.
Task: to calculate, at least roughly, what equipment is needed to organize a failover cluster of servers.
Maybe some more information is needed?
I would be grateful for any help, advice or a kick in the right direction :)
Thank you!

Answer 1

-2Gb RAM per core (ex 8Gb for Quad-core)
-2 dual cores is better than one quad
-64Mb per user + 2GB per OS. For example 100 users*64Mb + 2048=8.4Gb (this is the minimum)
-15 sessions per core
-Performance drops if the percentage of CPU time per core is consistently above 65%
-Performance doubles at 64 bits
ref
In your case.
1000 users = 66 cores (8 servers of 8, or 4 of 16)
We look further.
8 servers = 150 users each. 150 users *200Mb (applications)+2000=32Gb per server.
Also worth reading technet

Answer 2

Thanks a lot! In parallel, I read everything, but it never hurts to ask knowledgeable people!