LUDOC-11 changelog: describe changelog space usage

[doc/manual.git] / SystemConfigurationUtilities.xml

diff --git a/SystemConfigurationUtilities.xml b/SystemConfigurationUtilities.xml
index 40a179d..b3c1fc7 100644 (file)
--- a/SystemConfigurationUtilities.xml
+++ b/SystemConfigurationUtilities.xml
@@ -601,7 +601,14 @@ $ lctl conf_param testfs.llite.max_read_ahead_mb=16 </screen>
                 <para> <literal>changelog_register</literal></para>
               </entry>
               <entry>
-                <para> Registers a new changelog user for a particular device. Changelog entries are not purged beyond a registered user&apos;s set point (see <literal>lfs changelog_clear</literal>).</para>
+                <para> Registers a new changelog user for a particular device.
+               Changelog entries are saved persistently on the MDT with each
+               filesystem operation, and are only purged beyond all registered
+               user&apos;s minimum set point (see
+               <literal>lfs changelog_clear</literal>). This may cause the
+               Changelog to consume a large amount of space, eventually
+               filling the MDT, if a changelog user is registered but never
+               consumes those records.</para>
               </entry>
             </row>
             <row>
@@ -609,7 +616,10 @@ $ lctl conf_param testfs.llite.max_read_ahead_mb=16 </screen>
                 <para>changelog_deregister <replaceable>id</replaceable></para>
               </entry>
               <entry>
-                <para> Unregisters an existing changelog user. If the user&apos;s &quot;clear&quot; record number is the minimum for the device, changelog records are purged until the next minimum.</para>
+                <para> Unregisters an existing changelog user. If the
+               user&apos;s &quot;clear&quot; record number is the minimum for
+               the device, changelog records are purged until the next minimum.
+               </para>
               </entry>
             </row>
           </tbody>