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<title>Understanding logical device migration</title>

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<h1>Understanding logical device migration</h1>
<p>Logical device migration is a powerful and flexible feature of controllers in a HP Storage Manager system.
  You can use logical device migration to:</p>
<ul>
  <li><a href="achgrlcc.htm">Change the RAID level of existing logical devices</a></li>
  <li><a href="aexpldcc.htm">Increase the size of an existing logical device</a></li>
</ul>
<p>You can migrate a logical device while the server is running with only minor
  performance degradation for users during the process. You can start the migration
  immediately or <a href="ctskschd.htm">schedule</a> it for a later date and time.
</p>
<p><img src="images/hstraid1.gif" width="37" height="32">&nbsp;HostRAID controllers
  do <strong>not</strong> support logical device migration.</p>
<p> <b><img src="images/note.gif" width="15" height="17"> Notes:</b> To perform
  a logical-drive migration, the following must be true:</p>
<ol>
  <li> The logical device that you have selected to migrate must be in the optimal
    state. <br>
    <br>
  </li>
  <li>The logical device cannot be configured with RAID level-10 or RAID level-50.</li>
</ol>
<p>If a physical drive fails during a logical device migration and you are migrating
  between RAID levels other than RAID level-0, the migration will continue and
  complete. Then, you must replace and rebuild the failed physical drive. </p>
<p>Logical device migrations also can recover from a power failure. If power is
  lost to the server during a logical device migration, the migration will restart
  as soon as power is restored and complete without data corruption.</p>

<h2>More information</h2>

<ul>
  <li><a href="cchgraid.htm">Things to consider when changing the RAID level</a></li>
  <li><a href="cmorelds.htm">Example: Increasing logical device size</a></li>
  <li><a href="ctskschd.htm">Understanding scheduled tasks</a></li>
  <li><a href="mtskmain.htm">Using the Task Manager</a></li>
</ul>

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