Add an entry about "proc: table is full" errors.

PR:		31857
Submitted by:	Michael Lucas <mwlucas@blackhelicopters.org>

en_US.ISO8859-1/books/faq/book.sgml

@@ -3890,6 +3890,49 @@ quit</programlisting>
         </answer>
       </qandaentry>
 
+      <qandaentry>
+        <question id="proc-table-full">
+          <para>Why do I get the error <errorname>/kernel: proc: table
+            is full</errorname>?</para>
+        </question>
+
+        <answer>
+          <para>The FreeBSD kernel will only allow a certain number of
+            processes to exist at one time.  The number is based on
+            the <literal>MAXUSERS</literal> option in the kernel
+            configuration.  <literal>MAXUSERS</literal> also affects
+            various other in-kernel limits, such as network buffers
+            (see <link linkend="panic-kmemmap-too-small">this</link>
+            earlier question).  If your machine is heavily loaded, you
+            probably want to increase <literal>MAXUSERS</literal>.
+            This will increase these other system limits in addition
+            to the maximum number of processes.</para>
+
+          <para>After FreeBSD 4.4, <literal>MAXUSERS</literal> became
+            a tunable value that could be set with
+            <varname>kern.maxusers</varname> in
+            <filename>/boot/loader.conf</filename>.  In earlier
+            versions of FreeBSD, you need to adjust
+            <literal>MAXUSERS</literal> in your kernel
+            configuration.</para>
+
+          <para>If your machine is lightly loaded, and you are simply
+            running a very large number of processes, you can adjust
+            this with the <varname>kern.maxproc</varname> sysctl.  If
+            these processes are being run by a single user, you will
+            also need to adjust <varname>kern.maxprocperuid</varname>
+            to be one less than your new
+            <varname>kern.maxproc</varname> value.  (It must be at
+            least one less because one system program, &man.init.8;,
+            must always be running.)</para>
+
+          <para>To make a sysctl permanent across reboots, set this in
+            <filename>/etc/sysctl.conf</filename> in recent versions
+            of FreeBSD, or <filename>/etc/rc.local</filename> in older
+            versions.</para>
+        </answer>
+      </qandaentry>
+
       <qandaentry>
         <question id="cmap-busy-panic">
           <para>Why do I get an error reading <errorname>CMAP