Since Filemaker advertises FMSA 11 as being able to serve more than 250 simultaneous users, I'm wondering if anyone has actually tested this to see what kind of load a system can handle? And in those situations, what kind of hardware and system architecture was used?

There are no good load simulation testing apps for FMP/FMS so it's virtually impossible to test in a lab.

As to "what kind of load a system can handle": impossible to say. With over say 50 users the architecture of the solution will play a crucial role.

One way to simulate is to use the OS monitoring tools and test with 5, 10, 20 users and extrapolate from there, keeping in mind that the load wouldn't exactly be linear but slightly exponential.

the matrix to determine the sweet spot of performance is always a moving target and specific to the physical hardware and network it's being run-on. In addition to the variables such as complexity of the solution and number of databases and tables, and related technologies (IWP/CWP)

My local restaurant has a sign over the door - Maximum occupancy 250 - that means that 250 souls can dine at this restaurant at one time however i suspect that if they were at capacity my experience for dining may not bode well.

Thanks for the replies. I wonder if any of the hosting companies have data on this, since they'd be the most likely to push the limits of the system. In my previous job, I never really pushed the limits at all. Probably 10 FMP users max and 5-10 IWP users. But if I try to push FMP in my new job, it's likely that the user counts could go well past 200 at any one time.

If ou expect that much load: take extra care to design for speed, and really beef up on the hardware, especially the hard disks and the network.

What Wim said, plus carefully select the OS, use high quality workstations as well.

Steven