IdP capacity / load testing advice

[Jerry Shipman]

Thanks again.

>> I am trying to figure out how to set up the IdP (or how many VMs I need, etc) in order to comfortably handle about 200 logins/second, which is (unless I screwed something up, which is always possible) the peak that I measured from our other (un-federated) login system.
> 
> I think that is vastly overestimating the load you'll see, but it's your environment. We don't see anything within an order of magnitude of that (no webmail admittedly). We do about 500,000 logins a day peak, more often closer to 250,000-300,000 and during summer much lower.
> 
> Even if you put 400,000 into an 8 hour window and ignore the other 16, the math doesn't come anywhere close to 200 per second. So maybe you have 4,000,000 logins a day through web?


The logins per day are not that high, no. But inside a day, not all of the seconds have the same number of logins. I think the peak seconds I found were probably some correlated event like "all of the students are trying to log in at 11:58p in order to submit the homework that is due at midnight" (just a guess). 
(Also, it's nice to have some excess capacity because once in a while you see infinite-loop-browser-bugs, or maybe deliberate attacks, etc.)

Jerry