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<title>Understanding logical device verification</title>

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<h1>Understanding logical device verification</h1>
<p>The purpose of verifying logical devices is to compute and write the parity
  data on the selected drives. Verifying a logical device confirms that the
  data redundancy for the logical device is correct. </p>
<p><b><img src="images/note.gif" width="15" height="17"> Note:</b>You can also verify a logical device
without writing the parity data. This type of verifiy
  is similar to Verify with fix&#8212;it checks the entire drive to ensure that there
  are no problems. However, unlike Verify with fix, Verify does not repair
  inconsistent or bad data. </p>


<h2>Using automatic verification</h2>
<p>If the logical device is attached to a controller that supports Build initialization,
  the HP Storage Manager automatically verifies all new RAID level-5
  and 50 logical devices. These logical devices must be verified before storing
  data. Verification ensures that the parity data is accurately computed.
  Accurate parity is critical for updating the parity when you begin to store
  data. </p>

<p><b><img src="images/note.gif" width="15" height="17"> Note:</b> The HP Storage Manager also the supports Build initialization
  for RAID level-1 and RAID level-10 logical devices. For these RAID levels, the HP Storage Manager automatically copies data from the
  primary drive to the mirror drive. </p>


<p>During Build initialization, the HP Storage Manager displays <img src="images/buildnew.gif" width="28" height="20">(in
  animation) in the Logical devices view, indicating that the operation is in
  progress. You can perform some actions on the controller during Build initialization,
  such as deleting a logical device; however, you <strong>cannot</strong> perform a
  logical device migration. Also, you can turn off the server during Build initialization
  and, when you turn on the server, the firmware will continue the build from
  where it left off. </p>


  <p><b><img src="images/note.gif" width="15" height="17"> Note:</b> You can determine
    if your controller firmware supports Build initialization and background consistency check
    by viewing the controller properties. The properties pane reports if these features
  are enabled or disabled.</p>


<h2>Using manual verification</h2>
<p>When you create a logical device that is attached to a controller that does
  <b>not</b> support Build initialization, you will receive a warning event in
  the <a href="cusegui5.htm">event viewer</a> stating that you must <b>manually</b>
  verify the logical device before storing data. Use &quot;<a href="asynchld.htm">Verify with fix</a>&quot;
  to manually verify the logical device. You must
  verify <b>new</b> RAID level-5 logical devices after you create them. </p>
<p>Manual verification can be a lengthy operation.
  You can verify the logical device immediately or <a href="ctskschd.htm">schedule</a>
  it for a later date and time. You can also schedule the verification as a
  recurring task. A recurring task starts at the initial start
  time, then runs periodically according to the given interval: the same time
  each day, each week, or each month. Do <b>not</b> turn off the server until
  the manual verification is complete. </p>

<h2>Using manual verification for background consistency check</h2>
<p>Background consistency check is an automatic background verification process. Background consistency check
  keeps data &quot;fresh&quot; by doing the following:</p>
<ul>
  <li>(For RAID level-5, 6, 5EE, 50, or 60) Reading data and rewriting the data parity.</li>
  <li> (For RAID level-1, 1E, or 10) Reading data and rewriting the mirror data.
  </li>
</ul>
<p>If background consistency check is disabled or your controller firmware does not support
  background consistency check, consider manually verifying your logical devices weekly.
  This does not alter data on the drive.</p>
<h2>More information</h2>

<ul>
  <li><a href="asynchld.htm">Verifying logical devices with fix</a> (action)</li>
  <li><a href="averifyld.htm">Verifying logical devices</a> (action)</li>
  <li><a href="adscrub.htm">Enabling and disabling background consistency check</a> (action)</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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