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<p>From Bryan, FYI.<br>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Subject:
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<td>LTO8 tape issue update</td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Date: </th>
<td>Tue, 16 Mar 2021 09:51:10 -0400</td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">From: </th>
<td>Bryan Hess <a class="moz-txt-link-rfc2396E" href="mailto:bhess@jlab.org"><bhess@jlab.org></a></td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">To: </th>
<td>Mark Ito <a class="moz-txt-link-rfc2396E" href="mailto:marki@jlab.org"><marki@jlab.org></a>, Nathan Baltzell
<a class="moz-txt-link-rfc2396E" href="mailto:baltzell@jlab.org"><baltzell@jlab.org></a>, Ole Hansen
<a class="moz-txt-link-rfc2396E" href="mailto:ole@jlab.org"><ole@jlab.org></a>, Brad Sawatzky <a class="moz-txt-link-rfc2396E" href="mailto:brads@jlab.org"><brads@jlab.org></a></td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">CC: </th>
<td>Graham Heyes <a class="moz-txt-link-rfc2396E" href="mailto:heyes@jlab.org"><heyes@jlab.org></a>, Jie Chen
<a class="moz-txt-link-rfc2396E" href="mailto:chen@jlab.org"><chen@jlab.org></a>, Andy Kowalski
<a class="moz-txt-link-rfc2396E" href="mailto:kowalski@jlab.org"><kowalski@jlab.org></a></td>
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<span style="margin: 0px; font-size: 12pt; color: rgb(0, 0, 0);
background-color: rgb(255, 255, 255);">An Update on the LTO8
tape issue: </span></div>
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We've worked with Chris and Ying and they are creating a
database table/web page for checking the status of the tape
recovery. Nothing fancy, but something that you can view to
see what files are in the recovery process. We should have
that for you soon. </div>
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Some good news: </div>
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<li>Since the New year we wrote 627TB on 54 LTO8 tapes that
were "just in case" duplicates to test LTO8. We have now
read those tapes back with zero errors. This validates the
growing consensus that we are past the write problem and
in the recovery phase.</li>
<li>Data center humidity trend data since Jan 1 shows that
we are staying in the new, tighter specification
(>55%). We will be watching this closely as we head
into summer. </li>
<li>With some database work I am getting better bounds on
the time window when we had the problem, and the drive
serial numbers of interest. To finish finding the tapes
that need recovery, we have stopped writing the "just in
case" duplicates and we are dedicating that tape bandwidth
to auditing suspect tapes. As a result, we have 15 more
tapes to go to IBM, and I suspect there will be more. <br>
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<li>IBM has refined their recovery tools, so we are going to
return some tapes for a second pass to see if they can
recover a greater fraction of the files.</li>
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<div style="margin:0px">Thanks for your patience during this
ongoing process. Please let me know if you have additional
questions. </div>
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<span style="margin:0px">--Bryan</span></div>
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