Linux / PostgreSQL question

I was just doing some huge operations with PostgreSQL and it all crashed out
with a "too many files open" message plastered all over the place..

Now in /proc/sys/fs/file-max there is only 4096, that limit could have
easily been reached. Does changing the value in the file effectively change
the limit system-wide? I changed it and rebooted but it was set right back
to 4096.. I've been out of the Linux loop for a long time (FreeBSD junkie
now) so I don't know how to set that up to permanently change the limit.

Marc: You use Linux, don't you? Have you ever run into this?

Any help is very appreciated, thanks!

-Mitch