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<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Sorry I can\u2019t help\u2026 the only thing going round and round my head right now is why on earth the existing controller cannot push the required firmware to the new one when it comes online. Never heard
of anything else! Feel free to name and shame so I can avoid </span><span style="font-family:"Segoe UI Emoji",sans-serif;mso-fareast-language:EN-US">😊</span><span style="mso-fareast-language:EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Richard<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> gpfsug-discuss-bounces@spectrumscale.org [mailto:gpfsug-discuss-bounces@spectrumscale.org]
<b>On Behalf Of </b>Buterbaugh, Kevin L<br>
<b>Sent:</b> 08 February 2018 16:00<br>
<b>To:</b> gpfsug main discussion list <gpfsug-discuss@spectrumscale.org><br>
<b>Subject:</b> [gpfsug-discuss] mmchdisk suspend / stop<o:p></o:p></span></p>
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<p class="MsoNormal">Hi All, <o:p></o:p></p>
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<p class="MsoNormal">We are in a bit of a difficult situation right now with one of our non-IBM hardware vendors (I know, I know, I KNOW - buy IBM hardware! <grin>) and are looking for some advice on how to deal with this unfortunate situation.<o:p></o:p></p>
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<p class="MsoNormal">We have a non-IBM FC storage array with dual-\u201credundant\u201d controllers. One of those controllers is dead and the vendor is sending us a replacement. However, the replacement controller will have mis-matched firmware with the surviving controller
and - long story short - the vendor says there is no way to resolve that without taking the storage array down for firmware upgrades. Needless to say there\u2019s more to that story than what I\u2019ve included here, but I won\u2019t bore everyone with unnecessary details.
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<p class="MsoNormal">The storage array has 5 NSDs on it, but fortunately enough they are part of our \u201ccapacity\u201d pool \u2026 i.e. the only way a file lands here is if an mmapplypolicy scan moved it there because the *access* time is greater than 90 days. Filesystem
data replication is set to one.<o:p></o:p></p>
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<p class="MsoNormal">So \u2026 what I was wondering if I could do is to use mmchdisk to either suspend or (preferably) stop those NSDs, do the firmware upgrade, and resume the NSDs? The problem I see is that suspend doesn\u2019t stop I/O, it only prevents the allocation
of new blocks \u2026 so, in theory, if a user suddenly decided to start using a file they hadn\u2019t needed for 3 months then I\u2019ve got a problem. Stopping all I/O to the disks is what I really want to do. However, according to the mmchdisk man page stop cannot be
used on a filesystem with replication set to one.<o:p></o:p></p>
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<p class="MsoNormal">There\u2019s over 250 TB of data on those 5 NSDs, so restriping off of them or setting replication to two are not options.<o:p></o:p></p>
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<p class="MsoNormal">It is very unlikely that anyone would try to access a file on those NSDs during the hour or so I\u2019d need to do the firmware upgrades, but how would GPFS itself react to those (suspended) disks going away for a while? I\u2019m thinking I could
be OK if there was just a way to actually stop them rather than suspend them. Any undocumented options to mmchdisk that I\u2019m not aware of???<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">Are there other options - besides buying IBM hardware - that I am overlooking? Thanks...<o:p></o:p></p>
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<p class="MsoNormal">\u2014<o:p></o:p></p>
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<p class="MsoNormal">Kevin Buterbaugh - Senior System Administrator<o:p></o:p></p>
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<p class="MsoNormal">Vanderbilt University - Advanced Computing Center for Research and Education<o:p></o:p></p>
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<p class="MsoNormal"><a href="mailto:Kevin.Buterbaugh@vanderbilt.edu">Kevin.Buterbaugh@vanderbilt.edu</a> - (615)875-9633<o:p></o:p></p>
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