RDS Hardware Sizing and Capacity Planning Guidance.

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We always felt the need of Hardware capacity guidance and sizing information for Terminal Services or Remote Desktop services for Server 2008 R2, Whenever I am engaged in any architectural guidance discussion for RDS deployment i always get a question what needs to be taken into consideration while deciding the hardware configuration and to do capacity planning.

Here are some bullet points which I recommend to my partners and customers to consider:

  • 2GB Memory (RAM) is the optimum limit for each core of a CPU. E.g. If you have 4 GB RAM then for optimum performance there should be Dual core CPU.
  • 2 Dual Core CPU perform better then single Quad core processor.
  • Recommended bandwidth for LAN of 30 users and WAN of 20 users.  Bandwidth (b) = 100 megabits per second (Mbps) with Latency (l) Less than 5 milliseconds.
  • On a Terminal Server 64 MB per user is the Ideal Memory (RAM) requirement for GP Only use + 2 GB for OS E.g. (100 users * 64) + 2000 = 8.4 GB i.e. 8GB RAM.
  • More applications used (i.e. Office, CAD Apps and etc.) will require more memory per user to be added to this calculation over the 64 MB base memory per user.
  • 15 TS session per CPU core is the optimum performance limit of a Terminal Server.
  • Network should not have more than 5 hops, and latency should be under 100ms.
  • 64 kbps is the Ideal Bandwidth per user session. (256 color, switched network, bitmap caching only)
  • CPU performance degrades if %processor time per core is constantly above 65%.
  • Terminal servers performance doubles when it is running on a X64 HW and OS.

In addition to that, Microsoft has just released a whitepaper on Capacity Planning in Windows Server 2008 R2.

Download it here

The Remote Desktop Session Host (RD Session Host) role service lets multiple concurrent users run Windows®-based applications on a remote computer running Windows Server® 2008 R2. This white paper is intended as a guide for capacity planning of RD Session Host in Windows Server 2008 R2. It describes the most relevant factors that influence the capacity of a given deployment, methodologies to evaluate capacity for specific deployments, and a set of experimental results for different combinations of usage scenarios and hardware configurations.

You can also use this document for sizing Terminal Services on a Hyper V Platform

Also use the Remote Desktop Load Simulation Tools available at following link to do the load testing for number of users on RDS Server

Download it here

I hope it helps, Let me know if you have any questions.

Cheers..