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The "danger" of using tunefs.lustre command is that you could trash
your lustre configuration if using it without understanding, so of
course before you use it make sure you understand what actually it is
going to do. It should be always possible to reconstruct the
configuration if you know exactly how your lustre filesystem was
configured in the first place. tunefs.lustre does not touch the data
itself therefore can not destroy them however unwise use of this tool
can make your filesystem unusable so retain cautious when using it.<br>
<br>
Before doing <br>
tunefs.lustre --writeconf /dev/<lustre target device><br>
make sure your lustre file system is completely stopped<br>
<br>
Good luck!<br>
<br>
Thomas Roth wrote:
<blockquote cite="mid:49661926.70702@gsi.de" type="cite">
<pre wrap="">Hi Wojciech,
thanks for your explanation of writeconf.
Of course, the man pages as well as the Lustre manual state that
writeconf is a potentially dangerous operation.
I'm always afraid to manipulate the MDT: might go wrong and I end up
with 100's of TB of junk (as a restore of backups never works once you
need it).
But if it's harmless to run writeconf as you said, I will try...
Regards,
Thomas
Wojciech Turek wrote:
</pre>
<blockquote type="cite">
<pre wrap="">writeconf forces all the lustre targets (OSTs and MDTs) to fetch fresh lustre
configuration logs from MGS. Therefore it is not critical if you don't run it
when upgrading lustre because most of the time your lustre configuration won't
change and everything will work seamlessly. However it is been considered as
best practice to run writeconf on all lustre targets when upgrading. Some times
new version of lustre may introduce some new features to the lustre
configuration which won't be picked up correctly until one rewrite the
configuration using writeconf.
I think that when upgrading from lustre 1.6.4 to 1.6.5 or 1.6.6 one need to run
writeconf in order to use new quota format introduced with lustre version 1.6.5,
please correct me if I am wrong.
I would recommend to run writeconf on occasion of lustre upgrade as it is
harmless and helps avoid problems that may arise in the future.
Cheers,
Wojciech
Jerome, Ron wrote:
</pre>
<blockquote type="cite">
<pre wrap="">For what it's worth, I've upgraded through every version of the Lustre
1.6.x series starting at 1.6.0 and now running 1.6.6 on a production
cluster (32TB in size with 5 OSS's 15 OST's and one MDS/MDT) and I have
never once ran tunefs.luster.... during the upgrade process.
Ron Jerome
National Research Council Canada.
</pre>
<blockquote type="cite">
<pre wrap="">-----Original Message-----
From: <a class="moz-txt-link-abbreviated" href="mailto:lustre-discuss-bounces@lists.lustre.org">lustre-discuss-bounces@lists.lustre.org</a> [<a class="moz-txt-link-freetext" href="mailto:lustre-discuss">mailto:lustre-discuss</a>-
<a class="moz-txt-link-abbreviated" href="mailto:bounces@lists.lustre.org">bounces@lists.lustre.org</a>] On Behalf Of Jakob Goldbach
Sent: January 7, 2009 9:41 AM
To: lustre-discuss
Subject: [Lustre-discuss] 1.6.5.1 <-> 1.6.6
Hi,
The manual says I need to
tunefs.lustre --mgs --writeconf ...
when upgrading from 1.6.5.1 to 1.6.6.
Whats happens if I want to downgrade to 1.6.5.1 again ?
I come from 1.6.4.3 - does that make a difference ?
Thanks
/Jakob
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</blockquote>
<pre wrap="">--
Wojciech Turek
Assistant System Manager
High Performance Computing Service
University of Cambridge
Email: <a class="moz-txt-link-abbreviated" href="mailto:wjt27@cam.ac.uk">wjt27@cam.ac.uk</a>
Tel: (+)44 1223 763517
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</pre>
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<pre wrap=""><!---->
</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Wojciech Turek
Assistant System Manager
High Performance Computing Service
University of Cambridge
Email: <a class="moz-txt-link-abbreviated" href="mailto:wjt27@cam.ac.uk">wjt27@cam.ac.uk</a>
Tel: (+)44 1223 763517
</pre>
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