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     <h4 class="title">
      <a name="mysql-cluster-limitations-disk-data">
      </a>
      25.2.7.9 Limitations Relating to NDB Cluster Disk Data Storage
     </h4>
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  <a class="indexterm" name="idm46045123170080">
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  <p>
   <b>
    Disk Data object maximums and minimums.
   </b>
   Disk data objects are subject to the following maximums and
          minimums:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      Maximum number of tablespaces:
            2
      <sup>
       32
      </sup>
      (4294967296)
     </p>
    </li>
    <li class="listitem">
     <p>
      Maximum number of data files per tablespace:
            2
      <sup>
       16
      </sup>
      (65536)
     </p>
    </li>
    <li class="listitem">
     <p>
      The minimum and maximum possible sizes of extents for
            tablespace data files are 32K and 2G, respectively. See
      <a class="xref" href="create-tablespace.html" title="15.1.21 CREATE TABLESPACE Statement">
       Section 15.1.21, “CREATE TABLESPACE Statement”
      </a>
      , for more information.
     </p>
    </li>
   </ul>
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  <p>
   In addition, when working with NDB Disk Data tables, you should
        be aware of the following issues regarding data files and
        extents:
  </p>
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   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      Data files use
      <a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-datamemory">
       <code class="literal">
        DataMemory
       </code>
      </a>
      . Usage is
            the same as for in-memory data.
     </p>
    </li>
    <li class="listitem">
     <p>
      Data files use file descriptors. It is important to keep in
            mind that data files are always open, which means the file
            descriptors are always in use and cannot be re-used for
            other system tasks.
     </p>
    </li>
    <li class="listitem">
     <p>
      Extents require sufficient
      <a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-diskpagebuffermemory">
       <code class="literal">
        DiskPageBufferMemory
       </code>
      </a>
      ;
            you must reserve enough for this parameter to account for
            all memory used by all extents (number of extents times size
            of extents).
     </p>
    </li>
   </ul>
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  <p>
   <b>
    Disk Data tables and diskless mode.
   </b>
   Use of Disk Data tables is not supported when running the
          cluster in diskless mode.
  </p>
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