Load balancing with the server pool

[mmarco]

I have set up a notebook server for my university, to be used by the
students in their classes and homework. For the moment, we have just
one machine, but we are going to add another one. So we have to set it
up now.

My idea was to let one of them handle the web server, and then use the
server pool to send the different worksheets to one of the machines or
the other. If i have understood it well, the server pool will assign
the works to the workers just by following the order in the workers
list. But it could be possible that at a given moment one of the
machines is really busy (because for instance some student has sent a
very long computation) while the other is relatively free. Would it be
possible to make the pool aware of that, so that it sends the new
works to the free machine, even if it was the busy one's turn?