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    <div class="moz-cite-prefix">for my experience multipathd+ZFS works
      well, and it worked well usually.<br>
    </div>
    <div class="moz-cite-prefix">I just remove the broken disk when it
      happens, replace it and the new multipathd device is added once
      the disk is replaced, and then then I start resilvering.</div>
    <div class="moz-cite-prefix">Anyway I found out this not always
      works with some version of JBOD disk array/firmware.</div>
    <div class="moz-cite-prefix">Some Proware controller that I had did
      not recognize that a disk was replaced. But This is not a
      multipathd problem in my case.</div>
    <div class="moz-cite-prefix">So my hint is to try it out with your
      hardware and see how it behaves.<br>
    </div>
    <div class="moz-cite-prefix"><br>
    </div>
    <div class="moz-cite-prefix">On 26/04/2019 16:57, Kurt Strosahl
      wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:BN8PR09MB357083DC99E9212552387B41A73E0@BN8PR09MB3570.namprd09.prod.outlook.com">
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        <p style="margin-top:0;margin-bottom:0">Hey, thanks!</p>
        <p style="margin-top:0;margin-bottom:0"><br>
        </p>
        <p style="margin-top:0;margin-bottom:0">I tried the multipathing
          part you had down there and I couldn't get it to work... I did
          find that this worked though</p>
        <div><br>
          #I pick a victim device</div>
        <div>multipath -ll</div>
        <div>...</div>
        <div>mpathax (35000cca2680a8194) dm-49 HGST    ,HUH721010AL5200 </div>
        <div>size=9.1T features='0' hwhandler='0' wp=rw</div>
        <div>`-+- policy='service-time 0' prio=1 status=enabled</div>
        <div>  |- 1:0:10:0   sdj     8:144   active ready running</div>
        <div>  `- 11:0:9:0   sddy    128:0   active ready running</div>
        <div>#then I remove the device</div>
        <div>multipath -f mpathax</div>
        <div>#and verify that it is gone</div>
        <div>multipath -ll | grep mpathax</div>
        <div>#then I run the following, which seems to rescan for
          devices.</div>
        <div>multipath -v2</div>
        <div>Apr 26 10:49:06 | sdj: No SAS end device for
          'end_device-1:1'</div>
        <div>Apr 26 10:49:06 | sddy: No SAS end device for
          'end_device-11:1'</div>
        <div>create: mpathax (35000cca2680a8194) undef HGST   
          ,HUH721010AL5200 </div>
        <div>size=9.1T features='0' hwhandler='0' wp=undef</div>
        <div>`-+- policy='service-time 0' prio=1 status=undef</div>
        <div>  |- 1:0:10:0   sdj     8:144   undef ready running</div>
        <div>  `- 11:0:9:0   sddy    128:0   undef ready running</div>
        <div>#then its back</div>
        <div>multipath -ll mpathax</div>
        <div>mpathax (35000cca2680a8194) dm-49 HGST    ,HUH721010AL5200 </div>
        <div>size=9.1T features='0' hwhandler='0' wp=rw</div>
        <div>`-+- policy='service-time 0' prio=1 status=enabled</div>
        <div>  |- 1:0:10:0   sdj     8:144   active ready running</div>
        <div>  `- 11:0:9:0   sddy    128:0   active ready running</div>
        <div><br>
        </div>
        I still need to test it fully once I get the whole stack up and
        running, but this seems to be a step in the right direction.
        <p style="margin-top:0;margin-bottom:0"><br>
        </p>
        w/r,
        <div>Kurt<br>
          <br>
          <div style="color: rgb(0, 0, 0);">
            <hr style="display:inline-block;width:98%" tabindex="-1">
            <div id="divRplyFwdMsg" dir="ltr"><font
                style="font-size:11pt" face="Calibri, sans-serif"
                color="#000000"><b>From:</b> Jongwoo Han
                <a class="moz-txt-link-rfc2396E" href="mailto:jongwoohan@gmail.com"><jongwoohan@gmail.com></a><br>
                <b>Sent:</b> Friday, April 26, 2019 6:28 AM<br>
                <b>To:</b> Kurt Strosahl<br>
                <b>Cc:</b> <a class="moz-txt-link-abbreviated" href="mailto:lustre-discuss@lists.lustre.org">lustre-discuss@lists.lustre.org</a><br>
                <b>Subject:</b> Re: [lustre-discuss] ZFS and
                multipathing for OSTs</font>
              <div> </div>
            </div>
            <div>
              <div dir="ltr">Disk replacement with multipathd + zfs is
                somewhat not convenient.
                <div><br>
                </div>
                <div>step1: mark offline the disk you should replace
                  with zpool command</div>
                <div>step2: remove disk from multipathd table with
                  multipath -f <mpath id></div>
                <div>step3: replace disk</div>
                <div>step4: add disk to multipath table with multipath
                  -ll <mpath id></div>
                <div>step5:  replace disk in zpool with zpool replace</div>
                <div><br>
                </div>
                <div>try this in your test environment and tell us if
                  you have found anything interesting in the syslog.</div>
                <div>In my case replacing single disk in multipathd+zfs
                  pool triggerd massive udevd partition scan. </div>
                <div><br>
                </div>
                <div>Thanks</div>
                <div>Jongwoo Han</div>
              </div>
              <br>
              <div class="x_gmail_quote">
                <div dir="ltr" class="x_gmail_attr">2019년 4월 26일 (금) 오전
                  3:44, Kurt Strosahl <<a
                    href="mailto:strosahl@jlab.org" id="LPlnk629042"
                    class="OWAAutoLink" previewremoved="true"
                    moz-do-not-send="true">strosahl@jlab.org</a>>님이
                  작성:<br>
                </div>
                <blockquote class="x_gmail_quote" style="margin:0px 0px
                  0px 0.8ex; border-left:1px solid rgb(204,204,204);
                  padding-left:1ex">
                  <div dir="ltr">
                    <div
                      id="x_gmail-m_-296173503153998559divtagdefaultwrapper"
                      dir="ltr" style="font-size:12pt; color:rgb(0,0,0);
font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color
                      Emoji","Segoe UI
                      Emoji",NotoColorEmoji,"Segoe UI
                      Symbol","Android
                      Emoji",EmojiSymbols">
                      <p style="margin-top:0px; margin-bottom:0px">Good
                        Afternoon,</p>
                      <p style="margin-top:0px; margin-bottom:0px"><br>
                      </p>
                      <p style="margin-top:0px; margin-bottom:0px">   
                        As part of a new lustre deployment I've now got
                        two disk shelves connected redundantly to two
                        servers.  Since each disk has two paths to the
                        server I'd like to use multipathing for both
                        redundancy and improved performance.  I haven't
                        found examples or discussion about such a setup,
                        and was wondering if there are any resources out
                        there that I could consult.</p>
                      <p style="margin-top:0px; margin-bottom:0px"><br>
                      </p>
                      <p style="margin-top:0px; margin-bottom:0px">Of
                        particular interest would be examples of the
                        /etc/zfs/vdev_id.conf and any tuning that was
                        done.  I'm also wondering about extra steps that
                        may have to be taken when doing a disk
                        replacement to account for the multipathing. 
                        I've got plenty of time to experiment with this
                        process, but I'd rather not reinvent the wheel
                        if I don't have to.</p>
                      <p style="margin-top:0px; margin-bottom:0px"><br>
                      </p>
                      <p style="margin-top:0px; margin-bottom:0px">w/r,</p>
                      <div id="x_gmail-m_-296173503153998559Signature">
                        <div
                          id="x_gmail-m_-296173503153998559divtagdefaultwrapper"
                          dir="ltr" style="font-size:12pt;
                          color:rgb(0,0,0);
                          font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple
                          Color Emoji","Segoe UI
                          Emoji",NotoColorEmoji,"Segoe UI
                          Symbol","Android
                          Emoji",EmojiSymbols">
                          <p style="margin-top:0px; margin-bottom:0px"><span
id="x_gmail-m_-296173503153998559ms-rterangepaste-start"></span><span
                              style="color:rgb(51,51,51);
                              font-family:monospace; font-size:14.16px">Kurt
                              J. Strosahl</span><br
                              style="color:rgb(51,51,51);
                              font-family:monospace; font-size:14.16px">
                            <span style="color:rgb(51,51,51);
                              font-family:monospace; font-size:14.16px">System
                              Administrator: Lustre, HPC</span><br
                              style="color:rgb(51,51,51);
                              font-family:monospace; font-size:14.16px">
                            <span style="color:rgb(51,51,51);
                              font-family:monospace; font-size:14.16px">Scientific
                              Computing Group, Thomas Jefferson National
                              Accelerator Facility</span><span
                              id="x_gmail-m_-296173503153998559ms-rterangepaste-end"></span><br>
                          </p>
                        </div>
                      </div>
                    </div>
                  </div>
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              <div><br>
              </div>
              -- <br>
              <div dir="ltr" class="x_gmail_signature"><font
                  face="'courier new', monospace">Jongwoo Han</font>
                <div><font face="'courier new', monospace">+82-505-227-6108</font></div>
              </div>
            </div>
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      <pre class="moz-quote-pre" wrap="">_______________________________________________
lustre-discuss mailing list
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</pre>
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