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    <p><span style="color: rgb(37, 37, 37); font-family: sans-serif;
        font-size: 14px; font-style: normal; font-variant-ligatures:
        normal; font-variant-caps: normal; font-weight: normal;
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        background-color: rgb(255, 255, 255); text-decoration-style:
        initial; text-decoration-color: initial; display: inline
        !important; float: none;">There is no specific requirement in
        Lustre to create multiple MGS; one MGS will often suffice for
        many file systems in a subnet. <br>
      </span></p>
    <p><span style="color: rgb(37, 37, 37); font-family: sans-serif;
        font-size: 14px; font-style: normal; font-variant-ligatures:
        normal; font-variant-caps: normal; font-weight: normal;
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        background-color: rgb(255, 255, 255); text-decoration-style:
        initial; text-decoration-color: initial; display: inline
        !important; float: none;">You should have one MGT, it can be
        mounted on more than one MGS (but only one at a time). You need
        something in place that prevents it being mounted more than
        once. ZFS has that ability. <br>
      </span></p>
    <p>
      <img alt="File:Metadata Server HA Cluster Simple lowres v1.png"
src="http://wiki.lustre.org/images/6/6e/Metadata_Server_HA_Cluster_Simple_lowres_v1.png"
        height="364" width="602">
      <br>
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        !important; float: none;"></span></p>
    Brian Andrus<br>
    <br>
    <div class="moz-cite-prefix">On 11/1/2017 7:08 PM, Parag Khuraswar
      wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:006e01d3537f$84a78740$8df695c0$@citilindia.com">
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        <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I
            have two mds nodes. For HA purpose I mentioned –service node
            options<o:p></o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">mkfs.lustre
            --servicenode=10.2.1.204@o2ib --servicenode=10.2.1.205@o2ib
            --mgs /dev/mapper/mpathc<o:p></o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Do
            I have to mention mgt in command ?<o:p></o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">How
            many mgt’s we can have on one mds or mgs servers ?<o:p></o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
        <div>
          <p class="MsoNormal"><span
style="font-family:"Calibri","sans-serif";color:#1F497D">Regards,<o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-family:"Calibri","sans-serif";color:#1F497D">Parag<o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
        </div>
        <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
        <div>
          <div style="border:none;border-top:solid #B5C4DF
            1.0pt;padding:3.0pt 0in 0in 0in">
            <p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext">
                lustre-discuss
                [<a class="moz-txt-link-freetext" href="mailto:lustre-discuss-bounces@lists.lustre.org">mailto:lustre-discuss-bounces@lists.lustre.org</a>] <b>On
                  Behalf Of </b>Brian Andrus<br>
                <b>Sent:</b> Thursday, November , 2017 7:30 AM<br>
                <b>To:</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] mdt mounting error<o:p></o:p></span></p>
          </div>
        </div>
        <p class="MsoNormal"><o:p> </o:p></p>
        <p>I don't think you use the --servicenode option when
          formatting an mgs-only disk, or the --fsname option. Neither
          of those apply for an mgs-only with multiple filesystems.<o:p></o:p></p>
        <p>My command for a zfs backed mgs was:<o:p></o:p></p>
        <p><b><i>mkfs.lustre --mgs --backfstype=zfs MGT/mgt</i></b><o:p></o:p></p>
        <p>Then I created 2 different sets of OSTs/MDTs with different
          fsnames, but the same mgsnode.<o:p></o:p></p>
        <p>Brian Andrus<o:p></o:p></p>
        <p class="MsoNormal"><o:p> </o:p></p>
        <div>
          <p class="MsoNormal">On 11/1/2017 6:50 PM, Parag Khuraswar
            wrote:<o:p></o:p></p>
        </div>
        <blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
          <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Hi
              Raj,</span><o:p></o:p></p>
          <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
          <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">But
              I have two file system. And I think one mgt can be used
              for two filesystems. Correct me if I am wrong.</span><o:p></o:p></p>
          <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
          <p class="MsoNormal"><span
style="font-family:"Calibri","sans-serif";color:#1F497D">Regards,</span><o:p></o:p></p>
          <p class="MsoNormal"><span
style="font-family:"Calibri","sans-serif";color:#1F497D">Parag</span><o:p></o:p></p>
          <p class="MsoNormal"><span
style="font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
          <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
          <p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
              Raj [<a href="mailto:rajgautam@gmail.com"
                moz-do-not-send="true">mailto:rajgautam@gmail.com</a>] <br>
              <b>Sent:</b> Wednesday, November , 2017 4:57 PM<br>
              <b>To:</b> Parag Khuraswar; Lustre discussion<br>
              <b>Subject:</b> Re: [lustre-discuss] mdt mounting error</span><o:p></o:p></p>
          <p class="MsoNormal"> <o:p></o:p></p>
          <div>
            <p class="MsoNormal">The following can contribute to this
              issue:<o:p></o:p></p>
            <div>
              <p class="MsoNormal">- Missing FS name in mgt creation (it
                must be <=9 character long): --fsname=<o:p></o:p></p>
            </div>
            <div>
              <p class="MsoNormal"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">mkfs.lustre
                  <a href="mailto:--servicenode=10.2.1.204@o2ib"
                    moz-do-not-send="true">--servicenode=10.2.1.204@o2ib</a>
                  <a href="mailto:--servicenode=10.2.1.205@o2ib"
                    moz-do-not-send="true">--servicenode=10.2.1.205@o2ib</a>
                  <b>--fsname=home</b> --mgs /dev/mapper/mpathc</span><o:p></o:p></p>
            </div>
            <div>
              <p class="MsoNormal"> <o:p></o:p></p>
            </div>
            <div>
              <p class="MsoNormal"><span
style="font-size:13.5pt;font-family:"Calibri","sans-serif"">-
                  verify if /mdt directory exists</span><o:p></o:p></p>
            </div>
            <div>
              <p class="MsoNormal"> <o:p></o:p></p>
            </div>
            <div>
              <p class="MsoNormal"> <o:p></o:p></p>
            </div>
          </div>
          <p class="MsoNormal"> <o:p></o:p></p>
          <div>
            <div>
              <p class="MsoNormal">On Wed, Nov 1, 2017 at 6:16 AM Raj
                <<a href="mailto:rajgautam@gmail.com"
                  moz-do-not-send="true">rajgautam@gmail.com</a>>
                wrote:<o:p></o:p></p>
            </div>
            <blockquote style="border:none;border-left:solid #CCCCCC
              1.0pt;padding:0in 0in 0in
6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt">
              <p class="MsoNormal">What options in mkfs.lustre did you
                use to format with lustre?<o:p></o:p></p>
              <div>
                <div>
                  <p class="MsoNormal">On Wed, Nov 1, 2017 at 6:14 AM
                    Parag Khuraswar <<a
                      href="mailto:parag_k@citilindia.com"
                      target="_blank" moz-do-not-send="true">parag_k@citilindia.com</a>>
                    wrote:<o:p></o:p></p>
                </div>
                <blockquote style="border:none;border-left:solid #CCCCCC
                  1.0pt;padding:0in 0in 0in
6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt">
                  <div>
                    <div>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Hi
                          Raj,</span><o:p></o:p></p>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Yes,
                          /dev/mapper/mpatha available. </span><o:p></o:p></p>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I
                          could format and mount using ext4.</span><o:p></o:p></p>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Calibri","sans-serif";color:#1F497D">Regards,</span><o:p></o:p></p>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Calibri","sans-serif";color:#1F497D">Parag</span><o:p></o:p></p>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
                          Raj [mailto:<a
                            href="mailto:rajgautam@gmail.com"
                            target="_blank" moz-do-not-send="true">rajgautam@gmail.com</a>]
                          <br>
                          <b>Sent:</b> Wednesday, November , 2017 4:39
                          PM<br>
                          <b>To:</b> Parag Khuraswar; Lustre discussion<br>
                          <b>Subject:</b> Re: [lustre-discuss] mdt
                          mounting error</span><o:p></o:p></p>
                    </div>
                  </div>
                  <div>
                    <div>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
                      <p class="MsoNormal"
                        style="mso-margin-top-alt:auto;margin-bottom:12.0pt">Parag,
                        <br>
                        Is the device /dev/mapper/mpatha available? <br>
                        If not, the multipathd may not have started or
                        the multipath configuration may not be correct.
                        <o:p></o:p></p>
                      <div>
                        <div>
                          <p class="MsoNormal"
                            style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">On
                            Wed, Nov 1, 2017 at 5:18 AM Parag Khuraswar
                            <<a href="mailto:parag_k@citilindia.com"
                              target="_blank" moz-do-not-send="true">parag_k@citilindia.com</a>>
                            wrote:<o:p></o:p></p>
                        </div>
                        <blockquote style="border:none;border-left:solid
                          #CCCCCC 1.0pt;padding:0in 0in 0in
6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt">
                          <div>
                            <div>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91">Hi,</span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91"> </span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91">I
                                  am getting below error while mounting
                                  mdt. Mgt is mounted. </span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91"> </span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91">Please
                                  suggest</span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91"> </span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91">[root@mds2
                                  ~]# mount -t lustre /dev/mapper/mpatha
                                  /mdt</span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91">mount.lustre:
                                  mount /dev/mapper/mpatha at /mdt
                                  failed: No such file or directory</span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91">Is
                                  the MGS specification correct?</span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91">Is
                                  the filesystem name correct?</span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91">If
                                  upgrading, is the copied client log
                                  valid? (see upgrade docs)</span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="font-size:14.0pt;color:#365F91"> </span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="color:#365F91">Regards,</span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="color:#365F91">Parag</span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
                                  style="color:#365F91"> </span><o:p></o:p></p>
                              <p class="MsoNormal"
                                style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
                            </div>
                          </div>
                          <p class="MsoNormal"
                            style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">_______________________________________________<br>
                            lustre-discuss mailing list<br>
                            <a
                              href="mailto:lustre-discuss@lists.lustre.org"
                              target="_blank" moz-do-not-send="true">lustre-discuss@lists.lustre.org</a><br>
                            <a
                              href="http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org"
                              target="_blank" moz-do-not-send="true">http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org</a><o:p></o:p></p>
                        </blockquote>
                      </div>
                    </div>
                  </div>
                </blockquote>
              </div>
            </blockquote>
          </div>
          <p class="MsoNormal"><br>
            <br>
            <br>
            <o:p></o:p></p>
          <pre>_______________________________________________<o:p></o:p></pre>
          <pre>lustre-discuss mailing list<o:p></o:p></pre>
          <pre><a href="mailto:lustre-discuss@lists.lustre.org" moz-do-not-send="true">lustre-discuss@lists.lustre.org</a><o:p></o:p></pre>
          <pre><a href="http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org" moz-do-not-send="true">http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org</a><o:p></o:p></pre>
        </blockquote>
        <p class="MsoNormal"><o:p> </o:p></p>
      </div>
    </blockquote>
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