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<p class="MsoNormal">What is this manual header reconstruction you speak of? That doesn\u2019t sound trivial at all.
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<p class="MsoNormal"><b>From:</b> Oesterlin, Robert [mailto:Robert.Oesterlin@nuance.com]
<br>
<b>Sent:</b> Wednesday, July 26, 2017 12:46 PM<br>
<b>To:</b> gpfsug main discussion list <gpfsug-discuss@spectrumscale.org><br>
<b>Subject:</b> Re: [gpfsug-discuss] Lost disks<o:p></o:p></p>
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<p class="MsoNormal">One way this could possible happen would be a system is being installed (I\u2019m assuming this is Linux) and the FC adapter is active; then the OS install will see disks and wipe out the NSD descriptor on those disks. (Which is why the NSD
V2 format was invented, to prevent this from happening) If you don\u2019t lose all of the descriptors, it\u2019s sometimes possible to manually re-construct the missing header information - I\u2019m assuming since you opened a PMR, IBM has looked at this. This is a scenario
I\u2019ve had to recover from - twice. Back-end array issue seems unlikely to me, I\u2019d keep looking at the systems with access to those LUNs and see what commands/operations could have been run.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">Bob Oesterlin<br>
Sr Principal Storage Engineer, Nuance<o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black"><<a href="mailto:gpfsug-discuss-bounces@spectrumscale.org">gpfsug-discuss-bounces@spectrumscale.org</a>> on behalf of Mark Bush <<a href="mailto:Mark.Bush@siriuscom.com">Mark.Bush@siriuscom.com</a>><br>
<b>Reply-To: </b>gpfsug main discussion list <<a href="mailto:gpfsug-discuss@spectrumscale.org">gpfsug-discuss@spectrumscale.org</a>><br>
<b>Date: </b>Wednesday, July 26, 2017 at 12:29 PM<br>
<b>To: </b>"<a href="mailto:gpfsug-discuss@spectrumscale.org">gpfsug-discuss@spectrumscale.org</a>" <<a href="mailto:gpfsug-discuss@spectrumscale.org">gpfsug-discuss@spectrumscale.org</a>><br>
<b>Subject: </b>[EXTERNAL] [gpfsug-discuss] Lost disks<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black">I have a client has had an issue where all of the nsd disks disappeared in the cluster recently. Not sure if it\u2019s due to a back end disk issue or if it\u2019s 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\u2019t 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\u2019t 100% sure that
something at the disk array couldn\u2019t have caused this. </span><o:p></o:p></p>
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