<para>The striped directory feature is most useful for distributing
single large directories (50k entries or more) across multiple MDTs,
since it incurs more overhead than non-striped directories.</para>
+ <section xml:id="dbdoclet.lfsmkdirbyspace" condition='l2D'>
+ <title>Directory creation by space/inode usage</title>
+ <para>If the starting MDT is not specified when creating a new directory,
+ this directory and its stripes will be distributed on MDTs by space usage.
+ For example the following will create a directory and its stripes on MDTs
+ with balanced space usage:</para>
+ <screen>lfs mkdir -c 2 <dir1></screen>
+ <para>Alternatively, if a default directory stripe is set on a directory,
+ the subsequent syscall <literal>mkdir</literal> under
+ <literal><dir1></literal> will have the same effect:
+ <screen>lfs setdirstripe -D -c 2 <dir1></screen></para>
+ <para>The policy is:</para>
+ <itemizedlist>
+ <listitem><para>If free inodes/blocks on all MDT are almost the same,
+ i.e. <literal>max_inodes_avail * 84% < min_inodes_avail</literal> and
+ <literal>max_blocks_avail * 84% < min_blocks_avail</literal>, then
+ choose MDT roundrobin.</para></listitem>
+ <listitem><para>Otherwise, create more subdirectories on MDTs with more
+ free inodes/blocks.</para></listitem>
+ </itemizedlist>
+ </section>
</section>
<section xml:id="dbdoclet.50438194_88980">
<title>