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<h1 class="topictitle1">Main storage (memory) and save-while active</h1>
<div><p>How a save-while-active operation affects main storage depends on three
items:</p>
<ul><li>Pageable size of the machine pool</li>
<li>Job priority and pool usage</li>
<li>Number and size of objects</li>
</ul>
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<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="rzaiurzaiu334.htm">Performance considerations for save-while-active</a></div>
</div>
</div><div class="nested1" xml:lang="en-us" id="conceptSunDec051559222004"><a name="conceptSunDec051559222004"><!-- --></a><h2 class="topictitle2">Pageable size of the machine pool</h2>
<div><p>Additional pages are required in the machine pool for the server to use
during the save-while-active operation. Additionally, saving many small objects
or file members places additional requirements on the pageable portion of
the machine pool. You should consider the addition of 1200KB to the machine
pool a minimum. Additional memory may improve the response time and the save-time.</p>
<p>Additional megabytes of storage for the machine pool may help performance
if saving thousands of small objects or file members (less than 50KB object
sizes). You should monitor the machine pool for paging activity.</p>
</div>
</div>
<div class="nested1" xml:lang="en-us" id="conceptSunDec051600032004"><a name="conceptSunDec051600032004"><!-- --></a><h2 class="topictitle2">Job priority and pool usage</h2>
<div><p>You must decide which jobs have priority: the save operation or the other
activity on the server. You should give the save operation a lower priority
than the interactive jobs, but a higher priority than other batch jobs. This
priority will maintain the best response time for interactive jobs, but still
allow the save to complete as quickly as possible. In addition, separate the
save operation from other work on your server by using a separate memory pool.
The size of this separate pool should be a minimum of 10MB (16MB if you are
using a high speed tape device). The full synchronization and library synchronization
options generally require a few additional megabytes of memory. If there are
thousands of objects or file members in the save-while-active operation, you
should add more memory to the memory pool. This is especially true if the
objects are small. To determine the correct pool size for your server, monitor
the paging activity in the pool during a save and adjust the memory as necessary.
However, if the pool is a shared memory pool, then the settings in the system
value, QPFRADJ, will adjust its performance.</p>
</div>
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<div class="nested1" xml:lang="en-us" id="conceptSunDec051600352004"><a name="conceptSunDec051600352004"><!-- --></a><h2 class="topictitle2">Number and size of objects</h2>
<div><p>If you are saving many small objects or file members, the paging in the
machine pool may increase. You should monitor paging in the machine pool.
You should take steps to minimize paging to maintain better overall server
performance. These recommendations are also apply for normal save and restore
operations.</p>
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