LUDOC-484 misc: add identity_flush documentation

[doc/manual.git] / LustreProgrammingInterfaces.xml

diff --git a/LustreProgrammingInterfaces.xml b/LustreProgrammingInterfaces.xml
index cd3d44b..cb72cf0 100644 (file)
--- a/LustreProgrammingInterfaces.xml
+++ b/LustreProgrammingInterfaces.xml
@@ -1,4 +1,7 @@
-<?xml version='1.0' encoding='UTF-8'?><chapter xmlns="http://docbook.org/ns/docbook" xmlns:xl="http://www.w3.org/1999/xlink" version="5.0" xml:lang="en-US" xml:id="lustreprogramminginterfaces">
+<?xml version='1.0' encoding='UTF-8'?>
+<chapter xmlns="http://docbook.org/ns/docbook"
+ xmlns:xl="http://www.w3.org/1999/xlink" version="5.0" xml:lang="en-US"
+ xml:id="lustreprogramminginterfaces">
   <title xml:id="lustreprogramminginterfaces.title">Programming Interfaces</title>
   <para>This chapter describes public programming interfaces to that can be
     used to control various aspects of a Lustre file system from userspace.
@@ -81,7 +84,7 @@
               to complete, to avoid MDS threads and clients hanging due to
               errors accessing a remote service node.  The upcall must finish
               within 30s before the MDS will continue without the supplementary
-              data.  The upcall timeout can be set on the MDS using:
+              data.  The upcall timeout in seconds can be set on the MDS using:
               <literal>lctl set_param mdt.*.identity_acquire_expire=<replaceable>seconds</replaceable></literal></para>
           </listitem>
           <listitem>
@@ -95,9 +98,19 @@
             <para>The group downcall data is cached by the kernel to avoid
               repeated upcalls for the same user slowing down the MDS.  This
               cache is expired from the kernel after 1200s (20 minutes) by
-              default.  The cache age can be set on the MDS using:
+              default.  The cache age in seconds can be set on the MDS using:
               <literal>lctl set_param mdt.*.identity_expire=<replaceable>seconds</replaceable></literal></para>
           </listitem>
+          <listitem>
+            <para>To force eviction of cached identity data (e.g. after adding
+              or removing a user from a supplementary group), the cache entry
+              for a specific numeric UID can be flushed on the MDS using:
+              <literal>lctl set_param mdt.*.identity_flush=<replaceable>UID</replaceable></literal>
+              To flush the cached records for all users from cache, use
+              <literal>-1</literal> for the UID:
+              <literal>lctl set_param mdt.*.identity_flush=-1</literal>
+            </para>
+          </listitem>
         </itemizedlist>
       </section>
     </section>
@@ -116,3 +129,6 @@ struct identity_downcall_data{
     </section>
   </section>
 </chapter>
+<!--
+  vim:expandtab:shiftwidth=2:tabstop=8:
+  -->