I've been tasked with setting up a 3-tier SharePoint farm.

  1. Two load balanced webservers
  2. Two applications servers
  3. A SQL server

Everything is all set up and working with load balancing etc. etc.

My question is what do I do with the application servers?

  • Do I load balance the two application servers?
  • Do I cluster them?
  • Do I run certain services on each server?
  • Do I have the same services running on each server and SharePoint automatically chooses a server?

I'm not quite sure why we have two application servers. Currently I just have the same services running on each app server.

Any help/tips/explanations would be much appreciated.

Thanks, Jamie

  • So resilient web and app servers but not DB? – Chopper3 May 19 '11 at 10:19
  • @Chopper3, yeah, blame the "architects". – Jamie May 19 '11 at 10:22
  • Blame them? I'd kick them down a set of metal stairs if I were you – Chopper3 May 19 '11 at 10:25

Here are some example topologies:


What you do with the application servers largely depends on what services you are running in the farm and how heavy they are utilized (i.e. it depends on your requirements). SharePoint 2010 will handle it's own internal load balancing with the service applications, so no need to set those up behind a load balancer. It just depends which application servers you have activated to run those services.

Some services such as the search query role, might actually be good candidates to run on your front end web servers. That way if your application servers are unavailable users will still be able to perform search queries.

Other examples of how you might split up roles on your application servers might be to have a dedicated search crawler on one application server and then other services on the other.

There are endless possibilities of how to use the application servers, it mainly comes down to how your farm will be used.

Regarding your SQL Server, even though you only have a single server in place, you might want to consider installing that machine as a single node SQL Server cluster so that if you decide to add additional redundancy to your SQL Server tier you only have to add a node to the cluster. Migrating from a non-cluster environment to a cluster environment could be a pain depending on how large your farm is.


You do want to load balance the web front ends, but you do not want to load balance or cluster the Application Servers. The App servers should be where you run your Service Applications. These Service Applications can be started on more than one server. When they are started automatically on more than one server they are load balanced between the 2 app servers. If one goes down the server gets marked down and the other server handles the load by itself. When the other server comes back up it will eventually get marked as active again and load balancing will resume. I agree the query role should be located on the WFE. However in your situation I would run the Indexing Service on both App servers along with almost all of the other services so you get performance and redundancy.

You should also do proper performance testing to make sure your topology works and doesn't have a bottleneck. SharePoint is very flexible and things can be moved around later if needed. Also if your SQL server is virtual and can be automatically moved to another server in the event of a hardware issue, this mitigates your risk of not being clustered. However if it is a physical machine, I would recommend either a cluster or SharePoint 2010 now supports Mirroring so that might be a cheaper option without the SAN requirement.

Hope that helps, good luck!

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