[Fedora-directory-users] not enough file descriptors

[MJD Shop Account]

I have a problem with running out of file descriptors.  I get this repeating message periodically in the /opt/fedora-ds/slapd-<servername>/logs/errors file:
[02/Mar/2007:13:25:45 -0500] - Not listening for new connections - too many fds open
[02/Mar/2007:13:25:46 -0500] - Listening for new connections again
[02/Mar/2007:13:25:47 -0500] - Not listening for new connections - too many fds open
[02/Mar/2007:13:25:47 -0500] - Listening for new connections again
...

When this happens, the users cannot log in for long periods and get angry.  Imagine that.  I do have this in a multi-master configuration with a second master, which is different hardware and does not show this error.

I read the tuning page http://directory.fedora.redhat.com/wiki/Performance_Tuning#Linux, which recommends updating the filedescriptors limit like so:
echo "64000" > /proc/sys/fs/file-max

However mine is already well above that:
# cat /proc/sys/fs/file-max
128456

How much higher should I be setting it?  I am running RHEL 4 update 4, single Pentium III 1.4GHz processor, 1280MB of memory.

I don't have any settinsg in sysctl.conf or /etc/security/limites for soft/hard limits, how do I tell what the defaults on soft/hard limits are?