The FreeBSD kernel will only allow a certain number of processes to exist at one time. The number is based on the
<varname>kern.maxusers
</varname> <citerefentry><refentrytitle>sysctl
</refentrytitle><manvolnum>8
</manvolnum></citerefentry> variable.
<varname>kern.maxusers
</varname> also affects various other in-kernel limits, such as network buffers. If the machine is heavily loaded, increase
<varname>kern.maxusers
</varname>. This will increase these other system limits in addition to the maximum number of processes.