+ <listitem>
+ <para condition='l27'>(Optional) If you are upgrading from a release before Lustre
+ 2.7, to enable OST FIDs to also store the OST index (to improve
+ reliability of LFSCK and debug messages), <emphasis>after</emphasis>
+ the OSTs are mounted run once on each OSS:
+ <screen>oss# lctl set_param osd-ldiskfs.*.osd_index_in_idif=1</screen>
+ </para>
+ <note><para>Enabling the <literal>index_in_idif</literal> feature will
+ prevent the OST from being used by older versions of Lustre, so it
+ should only be enabled once it is known there is no need for the
+ OST to be downgraded to an earlier release.</para></note>
+ </listitem>
+ <listitem>
+ <para>If a new MDT was added to the filesystem, the new MDT must be
+ attached into the namespace by creating one or more
+ <emphasis>new</emphasis> DNE subdirectories with the
+ <literal>lfs mkdir</literal> command that use the new MDT:
+<screen>
+client# lfs mkdir -i <replaceable>new_mdt_index /testfs/new_dir</replaceable>
+</screen>
+ </para>
+ <para condition='l28'>In Lustre 2.8 and later, it is possible to
+ split a new directory across multiple MDTs by creating it with
+ multiple stripes:
+<screen>
+client# lfs mkdir -c 2 <replaceable>/testfs/new_striped_dir</replaceable>
+</screen>
+ </para>
+ <para condition='l2D'>In Lustre 2.13 and later, it is possible to set
+ the default striping on <emphasis>existing</emphasis> directories
+ so that new remote subdirectories are created on less-full MDTs:
+<screen>
+client# lfs setdirstripe -c 1 -i -1 <replaceable>/testfs/some_dir</replaceable>
+</screen>
+ </para>
+ </listitem>