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<chapter xml:id='chap-jvm-opts'
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version='5.0' xml:lang='en'
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<title>Tuning JVM Options</title>
<para>By default, OpenDJ installs with options appropriate for evaluation, not
for production.</para>
<indexterm><primary>Java</primary><secondary>Settings</secondary></indexterm>
<variablelist>
<para>You can change JVM options for the server in the QuickStart installer,
and alternatively using the Control Panel (Runtime Options > Java Settings),
or with the <command>dsjavaproperties</command> command after editing the
<varlistentry>
<term>Heap size</term>
<listitem>
<para>The JVM heap size by default is either 256 MB or 1 GB.</para>
<para>In production, use at least a 2 GB heap (-Xms2G -Xmx2G).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Server optimizations</term>
<listitem>
<para>Use -server to select the HotSpot Server VM.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>32-bit vs. 64-bit</term>
<listitem>
<para>For heap sizes over 4 GB on 64-bit systems use -d64.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Garbage collection</term>
<listitem>
<para>Use -XX:+UseConcMarkSweepGC to select the CMS garbage collector
for low GC pause times.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>New generation size</term>
<listitem>
<para>If your directory handles high throughput, set the new generation
size large enough for the JVM to avoid promoting short-lived objects
into the old gen space (-XX:NewSize=512M).</para>
</listitem>
</varlistentry>
</variablelist>
</chapter>