One of the biggest e-commerce site's here in Sweden like to generate hundreds of thousands of sessionfiles every day.
That slows down their website alot, and the poor server is struggling hard.

They asked me if I could do something about it. So I mounted the catalogue with sessionfiles on a tmpfs volume. And suddenly the site is much faster. I guess storing sessionfiles directly into RAM solved it :P

And yes, they are aware that a restart of the server removes the files.