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    <div class="moz-cite-prefix">Do you mean that Cinder will be
      confused by Nova's volumes in its volume group?<br>
      <br>
      Yeah, sure that would be similarly easy to implement. Thank you
      for the suggestion!<br>
      <br>
      Dan<br>
      <br>
      On 10/21/2014 03:10 PM, Duncan Thomas wrote:<br>
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cite="mid:CAOyZ2aGvWjjwWAnfPbt6wfm0nUf1QZw2kHsUwbk55pYN1xDS4g@mail.gmail.com"
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      <p>Sharing the vg with cinder is likely to cause some pain testing
        proposed features cinder reconciling backend with the cinder db.
        Creating a second vg sharing the same backend pv is easy and
        avoids all such problems.</p>
      <p>Duncan Thomas</p>
      <div class="gmail_quote">On Oct 21, 2014 4:07 PM, "Dan Genin" <<a
          moz-do-not-send="true" href="mailto:daniel.genin@jhuapl.edu">daniel.genin@jhuapl.edu</a>>
        wrote:<br type="attribution">
        <blockquote class="gmail_quote" style="margin:0 0 0
          .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello,<br>
          <br>
          I would like to add to DevStack the ability to stand up Nova
          with LVM ephemeral<br>
          storage. Below is a draft of the blueprint describing the
          proposed feature.<br>
          <br>
          Suggestions on architecture, implementation and the blueprint
          in general are very<br>
          welcome.<br>
          <br>
          Best,<br>
          Dan<br>
          <br>
          ========================<br>
          Enable LVM ephemeral storage for Nova<br>
          ========================<br>
          <br>
          Currently DevStack supports only file based ephemeral storage
          for Nova, e.g.,<br>
          raw and qcow2. This is an obstacle to Tempest testing of Nova
          with LVM ephemeral<br>
          storage, which in the past has been inadvertantly broken<br>
          (see for example, <a moz-do-not-send="true"
            href="https://bugs.launchpad.net/nova/+bug/1373962"
            target="_blank">https://bugs.launchpad.net/nova/+bug/1373962</a>),
          and to Tempest<br>
          testing of new features based on LVM ephemeral storage, such
          as LVM ephemeral<br>
          storage encryption.<br>
          <br>
          To enable Nova to come up with LVM ephemeral storage it must
          be provided a<br>
          volume group. Based on an initial discussion with Dean Troyer,
          this is best<br>
          achieved by creating a single volume group for all services
          that potentially<br>
          need LVM storage; at the moment these are Nova and Cinder.<br>
          <br>
          Implementation of this feature will:<br>
          <br>
           * move code in lib/cinder/cinder_backends/lvm to lib/lvm with
          appropriate<br>
             modifications<br>
          <br>
           * rename the Cinder volume group to something generic, e.g.,
          devstack-vg<br>
          <br>
           * modify the Cinder initialization and cleanup code
          appropriately to use<br>
             the new volume group<br>
          <br>
           * initialize the volume group in stack.sh, shortly before
          services are<br>
             launched<br>
          <br>
           * cleanup the volume group in unstack.sh after the services
          have been<br>
             shutdown<br>
          <br>
          The question of how large to make the common Nova-Cinder
          volume group in order<br>
          to enable LVM ephemeral Tempest testing will have to be
          explored. Although,<br>
          given the tiny instance disks used in Nova Tempest tests, the
          current<br>
          Cinder volume group size may already be adequate.<br>
          <br>
          No new configuration options will be necessary, assuming the
          volume group size<br>
          will not be made configurable.<br>
          <br>
          <br>
          _______________________________________________<br>
          OpenStack-dev mailing list<br>
          <a moz-do-not-send="true"
            href="mailto:OpenStack-dev@lists.openstack.org">OpenStack-dev@lists.openstack.org</a><br>
          <a moz-do-not-send="true"
            href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev"
            target="_blank">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><br>
          <br>
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      <pre wrap="">_______________________________________________
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</pre>
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