Advanced Queuing?

[Alan DeKok]

Lemaster, Rob wrote:
> Does FreeRADIUS have any advanced queuing abilities? If we restart a BRAS, it will try to authenticate between 30,000 to 60,000 users all at once. This can crash our RADIUS server. Does FreeRADIUS have any advanced queuing functionality that will enable it handle this sudden surge of traffic, or should we plan to upgrade our hardware? 

  "Advanced" queuing?  That's just simple queues...

  The server can queue up to 64k requests, and then pull requests out of
the queue for processing.  This queue size can be increased, but it's
generally not a good idea, because there are usually other factors that
mean a large queue won't help.  i.e. see below.

> If advanced queuing functionality is available, can you point me to some documentation on this feature?

  There's no documentation, because it "just works".  I fail to
understand why some software has a configuration that says "please don't
die under heavy load".

  See also:

http://freeradius.org/features/scalability.html

  As a side note, do some performance tests on your system.  If the
maximum authentication rate is 100 requests/s (say because of a
database), then it will take 600 seconds to authenticate 60,000 users.
At that point, you might look into running multiple machines.

  Alan DeKok.