increasing ulimit -n

[Alex Dean]

My MySQL server has run up against the OS's (RHEL 4) limit on maximum
number of open files.  This is causing queries to terminate badly, user
connections refused, and it's generally a bad situation.

I've been reading about how it's possible to raise this limit by setting
'ulimit -n' to some higher number.  It's currently at 1024.  The only
thing this machine does is MySQL, so there are no concerns about other
users, etc.  Before I make any changes, though, I was hoping someone
might help me figure out a reasonable way to increase this number.  This
is new territory, so I'm wanting to tread cautiously.

FYI : /proc/sys/fs/file-max (which I understand to be the limit on all
files opened by all processes) is 562523.  What other information is
pertinent?

thanks,
alex