[master] document that zone rate-limiters have a floor of 1/second

diff --git a/doc/arm/Bv9ARM-book.xml b/doc/arm/Bv9ARM-book.xml
index db5877c0b0f6419904b08bc2c3459444b654b147..1b396fc517271de5c5932f16d5ce7a03c0907237 100644 (file)
--- a/doc/arm/Bv9ARM-book.xml
+++ b/doc/arm/Bv9ARM-book.xml
@@ -7794,18 +7794,20 @@ avoid-v6-udp-ports {};
              </listitem>
            </varlistentry>
 
-            <varlistentry>
-              <term><command>notify-rate</command></term>
-              <listitem>
-                <para>
-                  The rate at which NOTIFY requests will be sent
-                  during normal zone maintenance operations. (NOTIFY
-                  requests due to initial zone loading are subject
-                  to a separate rate limit; see below.) The default is
-                  20 per second.
-                </para>
-              </listitem>
-            </varlistentry>
+           <varlistentry>
+             <term><command>notify-rate</command></term>
+             <listitem>
+               <para>
+                 The rate at which NOTIFY requests will be sent
+                 during normal zone maintenance operations. (NOTIFY
+                 requests due to initial zone loading are subject
+                 to a separate rate limit; see below.) The default is
+                 20 per second.
+                 The lowest possible rate is one per second; when set
+                 to zero, it will be silently raised to one.
+               </para>
+             </listitem>
+           </varlistentry>
 
            <varlistentry>
              <term><command>startup-notify-rate</command></term>
@@ -7815,6 +7817,8 @@ avoid-v6-udp-ports {};
                  when the name server is first starting up, or when
                  zones have been newly added to the nameserver.
                  The default is 20 per second.
+                 The lowest possible rate is one per second; when set
+                 to zero, it will be silently raised to one.
                </para>
              </listitem>
            </varlistentry>
@@ -7832,6 +7836,8 @@ avoid-v6-udp-ports {};
                  <command>serial-query-rate</command> option, an
                  integer, is the maximum number of queries sent
                  per second.  The default is 20 per second.
+                 The lowest possible rate is one per second; when set
+                 to zero, it will be silently raised to one.
                </para>
              </listitem>
            </varlistentry>