Recommend concurrent users per NST

mattk

There is already a similar post here, however, this thread seems outdated.

Has anyone had any experience, or some reference material, which shows the recommend number of users running on one Navision Service Tier in 2009 or 2013?

Does the same apply when accessing NAV through web services?

Also, is there a maximum number of NSTs which can be running on a server?

Thanks

bbrown

The responses I've gotten from Microsoft still seem to be quite vague and non-committal. That original post was in reference to NAV 2009. With NAV 2013 (and R2) the big change is that the service is now 64 bit. This allows it to access much more memory. Effectively all the memory on the server including virtual memory. So here's the "guidelines" I can give based on the information I have gotten:

1. They recommend a user load of between 75 to 150 users per service. But, again, they also tell me there has been no real load testing. So your results may vary. When I asked about memory sizing recommendations based on user count, they had no answer. Only to monitor usage and add memory as needed. A rather useless response when the need is to specify systems for a new install. They did tell me that the service has a hard upper memory limit of 250 GB.

2. They recommend that each service be installed in its own dedicated Windows Server.

3. I'm not aware of any limits to the number of services per DB.

4. 2013 NST will support Network Load Balancing. Not as a laod balancing solution, but as an HA solution.

Hope this helps....

mattk

Thanks for the tips, very helpful! I have two follow up questions if you don't mind.

Should the number of users per NST vary if users access NAV through web services? My understanding is that the business logic remains the same and so the number of users should not be affected much.

Is there a particular reason why each NST should have its own dedicated server? Let's say we use Virtual Machines, wouldn't having only one VM for each NST increase complexity (as we will have many NSTs)?

Thanks again for the help.

bbrown

mattk wrote:

...wouldn't having only one VM for each NST increase complexity (as we will have many NSTs)?

How large is your site? What are you seeing for complexity?

The reason for the separate Windows Servers is due to the memory handling behavior of a 64 bit service. The service has visibility to all the memory on the machine. So if two (or more) services are on the same machine, some of the services could use all the memory leaving none for the others. The general recommendation I've gotten from Microsoft is to place each on its own VM.

afarr

Thanks for the explanation.

SQL allows us to specify minimum and maximum limits on the amount of memory it uses. It's unfortunate that the same feature hasn't been implemented for NAV 2013 services.

It does mean that a client will need to buy more licences (not only for Windows but also, for example, for anti-virus packages), and more powerful hardware.