<div dir="ltr">it can happen for multiple reasons , one is a linux install, unfortunate there are significant more simpler explanations. Linux as well as BIOS in servers from time to time looks for empty disks and puts a GPT label on it if the disk doesn't have one, etc. this thread is explaining a lot of this : <div><br></div><div><a href="https://www.ibm.com/developerworks/community/forums/html/topic?id=77777777-0000-0000-0000-000014439222">https://www.ibm.com/developerworks/community/forums/html/topic?id=77777777-0000-0000-0000-000014439222</a></div><div><br></div><div>this is why we implemented NSD V2 format long time ago , unfortunate there is no way to convert an V1 NSD to a V2 nsd on an existing filesytem except you remove the NSDs one at a time and re-add them after you upgraded the system to at least GPFS 4.1 (i would recommend a later version like 4.2.3) </div><div><br></div><div>some more details are here in this thread :</div><div><br></div><div><a href="https://www.ibm.com/developerworks/community/forums/html/threadTopic?id=5c1ee5bc-41b8-4318-a74e-4d962f82ce2e">https://www.ibm.com/developerworks/community/forums/html/threadTopic?id=5c1ee5bc-41b8-4318-a74e-4d962f82ce2e</a><br></div><div><br></div><div>but a quick summary of the benefits of V2 are :</div><div><ul><li>‰ Support for GPT NSD
‰ <br></li><ul><li>Adds a standard disk partition table (GPT type) to NSDs
‰ </li><li>Disk label support for Linux
‰ </li></ul></ul></div><div><ul><li>New GPFS NSD v2 format provides the following benefits:
‰ <br></li><ul><li>Includes a partition table so that the disk is recognized as a GPFS device
‰ </li><li>Adjusts data alignment to support disks with a 4 KB physical block size ‰</li><li>Adds backup copies of some key GPFS data structures
‰ </li><li>Expands some reserved areas to allow for future growth</li></ul></ul></div><div>the main reason we can't convert from V1 to V2 is the on disk format changed significant so we would have to move on disk data which is very risky. </div><div><br></div><div>hope that explains this.</div><div><br></div><div>Sven<br><br><div class="gmail_quote"><div dir="ltr">On Wed, Jul 26, 2017 at 10:29 AM Mark Bush <<a href="mailto:Mark.Bush@siriuscom.com">Mark.Bush@siriuscom.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="EN-US" link="#0563C1" vlink="#954F72">
<div class="m_-2174014895272506606WordSection1">
<p class="MsoNormal">I have a client has had an issue where all of the nsd disks disappeared in the cluster recently. Not sure if it’s due to a back end disk issue or if it’s a reboot that did it. But in their PMR they were told that all that data is lost
now and that the disk headers didn’t appear as GPFS disk headers. How on earth could something like that happen? Could it be a backend disk thing? They are confident that nobody tried to reformat disks but aren’t 100% sure that something at the disk array
couldn’t have caused this. <u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Is there an easy way to see if there is still data on these disks?<u></u><u></u></p>
<p class="MsoNormal">Short of a full restore from backup what other options might they have?<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">The mmlsnsd -X show’s blanks for device and device type now.
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal"># mmlsnsd -X<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Disk name NSD volume ID Device Devtype Node name Remarks
<u></u><u></u></p>
<p class="MsoNormal">---------------------------------------------------------------------------------------------------<u></u><u></u></p>
<p class="MsoNormal">INGEST_FILEMGR_xis2301 0A23982E57FD995D - - <a href="http://ingest-filemgr01.a.fXXXXXXX.net" target="_blank">ingest-filemgr01.a.fXXXXXXX.net</a> (not found) server node<u></u><u></u></p>
<p class="MsoNormal">INGEST_FILEMGR_xis2301 0A23982E57FD995D - - <a href="http://ingest-filemgr02.a.fXXXXXXX.net" target="_blank">ingest-filemgr02.a.fXXXXXXX.net</a> (not found) server node<u></u><u></u></p>
<p class="MsoNormal">INGEST_FILEMGR_xis2302 0A23982E57FD9960 - - <a href="http://ingest-filemgr01.a.fXXXXXXX.net" target="_blank">ingest-filemgr01.a.fXXXXXXX.net</a> (not found) server node<u></u><u></u></p>
<p class="MsoNormal">INGEST_FILEMGR_xis2302 0A23982E57FD9960 - - <a href="http://ingest-filemgr02.a.fXXXXXXX.net" target="_blank">ingest-filemgr02.a.fXXXXXXX.net</a> (not found) server node<u></u><u></u></p>
<p class="MsoNormal">INGEST_FILEMGR_xis2303 0A23982E57FD9962 - - <a href="http://ingest-filemgr01.a.fXXXXXXX.net" target="_blank">ingest-filemgr01.a.fXXXXXXX.net</a> (not found) server node<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal"><b><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#253773"><u></u> <u></u></span></b></p>
<p class="MsoNormal"><b><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#253773">Mark</span></b><u></u><u></u></p>
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