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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">Hi Marc,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">Thanks for the pointer to the updated syntax. That indeed looks nicer.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US"><span style="mso-list:Ignore">(1)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">Asynchronous policy propagation sounds good in our scenario. We don\u2019t want to potentially interrupt other running experiments
by having to quiesce the filesystem for a new one coming online. It is useful to know that you could quiesce if desired. Presumably this is a secret flag one might pass to mmchpolicy?<o:p></o:p></span></p>
<p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></a></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US"><span style="mso-list:Ignore">(2)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">I was concerned about the evaluation time if I tried to set all extended attributes at creation time. That\u2019s why I thought
about adding a few \u2018system\u2019 defined tags which could later be used to link the files to an asynchronously applied policy on the home cluster. I think I calculated around 4,000 rules (dependent on the size of the attribute names and values), which might limit
the number of experiments supported on a single ingest file system. However, I can\u2019t envisage we will ever have 4,000 experiments running at once! I was really interested in why the limitation existed from a file-system architecture point of view.<o:p></o:p></span></p>
<p class="MsoListParagraph"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">Thanks for the responses.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">Luke.<o:p></o:p></span></p>
<p class="MsoListParagraph"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""> Marc A Kaplan [mailto:makaplan@us.ibm.com]
<br>
<b>Sent:</b> 18 June 2015 14:19<br>
<b>To:</b> gpfsug main discussion list; Luke Raimbach<br>
<b>Subject:</b> Re: [gpfsug-discuss] Placement Policy Installation and RDM Considerations<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Yes, you can do this. In release 4.1.1 you can write SET POOL 'x' ACTION(setXattr(...)) FOR FILESET(...) WHERE ...</span>
<br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">which looks nicer to some people than WHERE ( ... ) AND setXattr(...)<br>
</span><br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Answers:</span> <br>
<br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">(1) No need to quiesce. As the new policy propagates, nodes begin using it. So there can be a transition time when node A may be using the new policy but Node B has not started</span>
<br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">using it yet. If that is undesirable, you can quiesce. </span>
<br>
<br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">(2) Yes, 1MB is a limit on the total size in bytes of your policy rules. Do you have a real need for more? Would you please show us such a scenario? Beware that policy rules take some cpu cycles
to evaluate... So if for example, if you had several thousand SET POOL rules, you might notice some impact to file creation time.</span>
<br>
<br>
<span style="font-size:10.0pt;font-family:"Arial","sans-serif"">--marc of GPFS</span>
<br>
<br>
<br>
<br>
<span style="font-size:7.5pt;font-family:"Arial","sans-serif";color:#5F5F5F">From: </span><span style="font-size:7.5pt;font-family:"Arial","sans-serif"">Luke Raimbach <<a href="mailto:Luke.Raimbach@crick.ac.uk">Luke.Raimbach@crick.ac.uk</a>></span>
<br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif""> ... </span><br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">RULE 'RDMTEST'</span>
<br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif""> SET POOL 'instruments\u2019</span>
<br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif""> FOR FILESET</span>
<br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">('%GPFSRDM%10.01013%RDM%0ab34906-5357-4ca0-9d19-a470943db30a%RDM%8fc2395d-64c0-4ebd-8c71-0d2d34b3c1c0')</span>
<br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif""> WHERE SetXattr</span>
<br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">('user.rdm.parent','0ab34906-5357-4ca0-9d19-a470943db30a')</span>
<br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif""> AND SetXattr</span>
<br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif""> ('user.rdm.ingestor','8fc2395d-64c0-4ebd-8c71-0d2d34b3c1c0')</span>
<br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">RULE 'DEFAULT' SET POOL 'data'</span>
<br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif""> ...</span> <br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">(1) When I install a placement policy into the file system, does the file system need to quiesce? My suspicion is yes, because the policy needs to be consistent on all nodes performing I/O, but
I may be wrong.</span> <br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif""> ...</span> <br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">(2) What is the specific limitation for having a policy placement file no larger than 1MB?</span>
<br>
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif""> ...</span> <o:p>
</o:p></p>
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