ibm-information-center/dist/eclipse/plugins/i5OS.ic.rzam4_5.4.0.1/rzam4disablhldoptsupt.htm

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<title>Disable held optical file support</title>
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<h1 class="topictitle1">Disable held optical file support</h1>
<div><p>i5/OS™ is
shipped with held optical file support enabled. If desired, you may disable
it by using the Change Optical Attributes (CHGOPTA) command.</p>
<p> When held optical file support is disabled, a held file is not created
when a file fails to be archived to optical disk. When using this option,
it is up to the user application to manage recovery procedures for files that
fail to be archived. Consider the following scenarios:</p>
<p><strong>Scenario 1</strong></p>
<p>The application opens an optical file for a write operation, and then writes
data to the file. When you attempt to close the file, it fails because the
optical disk is full.</p>
<dl><dt class="dlterm">Held file support enabled</dt>
<dd>The file is still open, but becomes held. The file closes when the job
ends if it never closes successfully before the job ends. The file will remain
held until it is released. </dd>
</dl>
<dl><dt class="dlterm">Held file support disabled</dt>
<dd>The file is still open, but is not held. The file closes when the job
ends if it never closed successfully before the job ends. The file will not
become held, and all resources (virtual optical file) associated with the
held file will then be freed up.</dd>
</dl>
<p><strong>Scenario 2</strong></p>
<p>The application opens an optical file for write, and then writes data to
the file. The application then issues a Force Buffered Data API to ensure
the data is safe on nonvolatile storage. The iSeries™ server then loses power.</p>
<dl><dt class="dlterm">Held File Support Enabled </dt>
<dd>After the internal program load (IPL) of the iSeries server is completed the file
exists as a held optical file. All data that was successfully forced to disk
is recoverable. In other words, when you save the held file to optical storage,
all data written before the Force buffered data request will be saved.</dd>
</dl>
<dl><dt class="dlterm">Held File Support Disabled</dt>
<dd>After the IPL of the iSeries server is completed, the file does not exist
as a held optical file. All data written to this file on the previous open
instance is lost. The force data request had no effect.</dd>
</dl>
<p>It is important to note that when held optical file support is disabled,
forcing data to nonvolatile storage is meaningless. This is because data is
written to optical storage after the file closes successfully. The Force buffered
data function will force the data to the i5/OS disk, and you can use the held optical
file to recover the data after a power loss. Held files are the only mechanism
to recover data forced to nonvolatile storage after a power loss or other
unexpected error. Held file support is needed to recover any data from an
open instance that closes unsuccessfully. This effects the following application
program interfaces.</p>
<ul><li>Force Buffered Data HFS API (QHFFRCSF)<p>This API is allowed when held
file support is disabled but it will have no effect.</p>
</li>
<li>Synchronize File Changes IFS API fsync() <p>This API is allowed when held
file support is disabled but it will have no effect.</p>
</li>
<li>Synchronous write-through flag on Open Stream File HFS API (QHFOPNSF)<p>This
value is allowed, but will be treated as an asynchronous write-through flag.</p>
</li>
</ul>
<p>Use the CHGOPTA CL command to enable, disable or determine the current
status of held optical file support. After held optical file support is disabled,
it remains disabled for all optical users. You must enable held file support
for it to become active again.</p>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="rzam4heldoptfiles.htm" title="If the optical file system is unable to update the optical disk during a close function, the operation fails and the file is marked as held.">Held optical files</a></div>
</div>
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