<section xml:id="dbdoclet.50438199_54623">
<title><indexterm><primary>maintenance</primary><secondary>regenerating config logs</secondary></indexterm>
Regenerating Lustre Configuration Logs</title>
- <para>If the Lustre file system configuration logs are in a state where the file system cannot
- be started, use the <literal>writeconf</literal> command to erase them. After the
- <literal>writeconf</literal> command is run and the servers restart, the configuration logs
- are re-generated and stored on the MGS (as in a new file system).</para>
+ <para>If the Lustre file system configuration logs are in a state where
+ the file system cannot be started, use the
+ <literal>tunefs.lustre --writeconf</literal> command to regenerate them.
+ After the <literal>writeconf</literal> command is run and the servers
+ restart, the configuration logs are re-generated and stored on the MGS
+ (as with a new file system).</para>
<para>You should only use the <literal>writeconf</literal> command if:</para>
<itemizedlist>
<listitem>
<para>A server NID is being changed</para>
</listitem>
</itemizedlist>
- <para>The <literal>writeconf</literal> command is destructive to some configuration items (i.e., OST pools information and items set via <literal>conf_param</literal>), and should be used with caution. To avoid problems:</para>
- <itemizedlist>
- <listitem>
- <para>Shut down the file system before running the <literal>writeconf</literal> command</para>
- </listitem>
- <listitem>
- <para>Run the <literal>writeconf</literal> command on all servers (MDT first, then OSTs)</para>
- </listitem>
- <listitem>
- <para>Start the file system in this order:</para>
- <itemizedlist>
- <listitem>
- <para>MGS (or the combined MGS/MDT)</para>
- </listitem>
- <listitem>
- <para>MDT</para>
- </listitem>
- <listitem>
- <para>OSTs</para>
- </listitem>
- <listitem>
- <para>Lustre clients</para>
- </listitem>
- </itemizedlist>
- </listitem>
- </itemizedlist>
+ <para>The <literal>writeconf</literal> command is destructive to some
+ configuration items (e.g. OST pools information and tunables set via
+ <literal>conf_param</literal>), and should be used with caution.</para>
<caution>
- <para>The OST pools feature enables a group of OSTs to be named for file striping purposes. If you use OST pools, be aware that running the <literal>writeconf</literal> command erases <emphasis role="bold">all</emphasis> pools information (as well as any other parameters set via <literal>lctl conf_param</literal>). We recommend that the pools definitions (and <literal>conf_param</literal> settings) be executed via a script, so they can be reproduced easily after a <literal>writeconf</literal> is performed.</para>
+ <para>The OST pools feature enables a group of OSTs to be named for
+ file striping purposes. If you use OST pools, be aware that running
+ the <literal>writeconf</literal> command erases
+ <emphasis role="bold">all</emphasis> pools information (as well as
+ any other parameters set via <literal>lctl conf_param</literal>).
+ We recommend that the pools definitions (and
+ <literal>conf_param</literal> settings) be executed via a script,
+ so they can be regenerated easily after <literal>writeconf</literal>
+ is performed. However, tunables saved with <literal>lctl set_param
+ -P</literal> are <emphasis>not</emphasis> erased in this case.</para>
</caution>
+ <note>
+ <para>If the MGS still holds any configuration logs, it may be
+ possible to dump these logs to save any parameters stored with
+ <literal>lctl conf_param</literal> by dumping the config logs on
+ the MGS and saving the output:</para>
+<screen>
+mgs# lctl --device MGS llog_print <replaceable>fsname</replaceable>-client
+mgs# lctl --device MGS llog_print <replaceable>fsname</replaceable>-MDT0000
+mgs# lctl --device MGS llog_print <replaceable>fsname</replaceable>-OST0000
+</screen>
+ </note>
<para>To regenerate Lustre file system configuration logs:</para>
<orderedlist>
<listitem>
- <para>Shut down the file system in this order.</para>
+ <para>Stop the file system services in the following order before
+ running the <literal>tunefs.lustre --writeconf</literal> command:
+ </para>
<orderedlist>
<listitem>
<para>Unmount the clients.</para>
</listitem>
<listitem>
- <para>Unmount the MDT.</para>
+ <para>Unmount the MDT(s).</para>
</listitem>
<listitem>
- <para>Unmount all OSTs.</para>
+ <para>Unmount the OST(s).</para>
+ </listitem>
+ <listitem>
+ <para>If the MGS is separate from the MDT it can remain mounted
+ during this process.</para>
</listitem>
</orderedlist>
</listitem>
<listitem>
- <para>Make sure the the MDT and OST devices are available.</para>
+ <para>Make sure the MDT and OST devices are available.</para>
</listitem>
<listitem>
- <para>Run the <literal>writeconf</literal> command on all servers.</para>
- <para>Run writeconf on the MDT first, and then the OSTs.</para>
+ <para>Run the <literal>tunefs.lustre --writeconf</literal> command
+ on all target devices.</para>
+ <para>Run writeconf on the MDT(s) first, and then the OST(s).</para>
<orderedlist>
<listitem>
- <para>On the MDT, run:</para>
- <screen>mdt# tunefs.lustre --writeconf <replaceable>/dev/mdt_device</replaceable></screen>
+ <para>On each MDS, for each MDT run:</para>
+ <screen>mds# tunefs.lustre --writeconf <replaceable>/dev/mdt_device</replaceable></screen>
</listitem>
<listitem>
- <para>
- On each OST, run:
-
- <screen>ost# tunefs.lustre --writeconf <replaceable>/dev/ost_device</replaceable></screen>
+ <para> On each OSS, for each OST run:
+ <screen>oss# tunefs.lustre --writeconf <replaceable>/dev/ost_device</replaceable></screen>
</para>
</listitem>
</orderedlist>
</listitem>
<listitem>
- <para>Restart the file system in this order.</para>
+ <para>Restart the file system in the following order:</para>
<orderedlist>
<listitem>
- <para>Mount the MGS (or the combined MGS/MDT).</para>
+ <para>Mount the separate MGT, if it is not already mounted.</para>
</listitem>
<listitem>
- <para>Mount the MDT.</para>
+ <para>Mount the MDT(s) in order, starting with MDT0000.</para>
</listitem>
<listitem>
- <para>Mount the OSTs.</para>
+ <para>Mount the OSTs in order, starting with OST0000.</para>
</listitem>
<listitem>
<para>Mount the clients.</para>
</orderedlist>
</listitem>
</orderedlist>
- <para>After the <literal>writeconf</literal> command is run, the configuration logs are re-generated as servers restart.</para>
+ <para>After the <literal>tunefs.lustre --writeconf</literal> command is
+ run, the configuration logs are re-generated as servers connect to the
+ MGS.</para>
</section>
<section xml:id="dbdoclet.changingservernid">
<title><indexterm><primary>maintenance</primary><secondary>changing a NID</secondary></indexterm>
git://git.whamcloud.com / doc / manual.git / blobdiff