necessarily chosen each time.</para>
</listitem>
</itemizedlist>
- <para>The allocation method is determined by the amount of free-space imbalance on the OSTs.
- When free space is relatively balanced across OSTs, the faster round-robin allocator is
- used, which maximizes network balancing. The weighted allocator is used when any two OSTs
- are out of balance by more than the specified threshold (17% by default). The threshold
- between the two allocation methods is defined in the file
- <literal>/proc/fs/<replaceable>fsname</replaceable>/lov/<replaceable>fsname</replaceable>-mdtlov/qos_threshold_rr</literal>. </para>
- <para>To set the <literal>qos_threshold_r</literal> to <literal>25</literal>, enter this
- command on the
- MGS:<screen>lctl set_param lov.<replaceable>fsname</replaceable>-mdtlov.qos_threshold_rr=25</screen></para>
+ <para>The allocation method is determined by the amount of free-space
+ imbalance on the OSTs. When free space is relatively balanced across
+ OSTs, the faster round-robin allocator is used, which maximizes network
+ balancing. The weighted allocator is used when any two OSTs are out of
+ balance by more than the specified threshold (17% by default). The
+ threshold between the two allocation methods is defined by the
+ <literal>qos_threshold_rr</literal> parameter. </para>
+ <para>To temporarily set the <literal>qos_threshold_rr</literal> to
+ <literal>25</literal>, enter the folowing on each MDS:
+ <screen>mds# lctl set_param lod.<replaceable>fsname</replaceable>*.qos_threshold_rr=25</screen></para>
</section>
<section remap="h3">
<title><indexterm>
<primary>space</primary>
<secondary>location weighting</secondary>
</indexterm>Adjusting the Weighting Between Free Space and Location</title>
- <para>The weighting priority used by the weighted allocator is set in the file
- <literal>/proc/fs/<replaceable>fsname</replaceable>/lov/<replaceable>fsname</replaceable>-mdtlov/qos_prio_free</literal>.
- Increasing the value of <literal>qos_prio_free</literal> puts more weighting on the amount
- of free space available on each OST and less on how stripes are distributed across OSTs. The
- default value is <literal>91</literal> (percent). When the free space priority is set to
+ <para>The weighting priority used by the weighted allocator is set by the
+ the <literal>qos_prio_free</literal> parameter.
+ Increasing the value of <literal>qos_prio_free</literal> puts more
+ weighting on the amount of free space available on each OST and less
+ on how stripes are distributed across OSTs. The default value is
+ <literal>91</literal> (percent). When the free space priority is set to
<literal>100</literal> (percent), weighting is based entirely on free space and location
is no longer used by the striping algorithm. </para>
- <para>To change the allocator weighting to <literal>100</literal>, enter this command on the
+ <para>To permanently change the allocator weighting to <literal>100</literal>, enter this command on the
MGS:</para>
- <screen>lctl conf_param <replaceable>fsname</replaceable>-MDT0000.lov.qos_prio_free=100</screen>
+ <screen>lctl conf_param <replaceable>fsname</replaceable>-MDT0000-*.lod.qos_prio_free=100</screen>
<para> .</para>
<note>
<para>When <literal>qos_prio_free</literal> is set to <literal>100</literal>, a weighted