[Server-devel] testing ejabberd

[Douglas Bagnall]

I wrote:
> I've written up my recent testing of ejabberd for the wiki:
>
> http://wiki.laptop.org/go/Ejabberd_resource_tests
>
> It is not completely satisfactory: I don't have the resources to test
> up to 3000 active users which I believe is an important target.  At
> lower numbers, however, ejabberd's memory consumption seems to be
> linear, and it looks to be roughly the case that 0.5 GB per 1000 users
> is enough.  (Just barely -- that's a limit, not a recommendation).

Since then, thanks to hyperactivity pointers from Guillaume, I got
ejabberd to very briefly accept about 4700 connections, and almost
simultaneously, to crash.  I'm quite pleased with this on both counts,
even though, because it happened during the period late on Fridays
that our host company offers free beer upstairs, I did not actually
witness the events.

The results are summarised here:

http://wiki.laptop.org/go/Ejabberd_resource_tests#Try_4:_a_few_thousand_users

In short, with 1GB ram, ejabberd coped with a stable load of 2000
connections, but it went crazy when faced with more, bouncing off the
RAM ceiling, dropping clients, and freezing its web admin interface.
Then after a quiet period it recuperated and gamely made the fatal
number of connections.