Tune JVM settings

This section gives some initial guidance on configuring the JVM for running AM when the deployment has a dedicated CTS token store, and AM is configured to use server-side sessions.

These settings provide a strong foundation to the JVM before a more detailed garbage collection tuning exercise, or as best practice configuration for production:

Heap Size Settings
JVM parameters	Suggested value	Description
`-Xms` & `-Xmx`	At least 1 GB (2 GB with embedded DS), in production environments at least 2 GB to 3 GB. This setting depends on the available physical memory, and on whether a 32- or 64-bit JVM is used.
`-XX:MetaspaceSize` & `-XX:MaxMetaspaceSize`	Set both to 256 MB	Controls the size of the metaspace in the JVM
`-Dsun.net.client.defaultReadTimeout`	60000	Controls the read timeout in the Java HTTP client implementation. This applies only to the Sun/Oracle HotSpot JVM.
`-Dsun.net.client.defaultConnectTimeout`	High setting: 30000 (30 seconds)	Controls the connect timeout in the Java HTTP client implementation When you have hundreds of incoming requests per second, reduce this value to avoid a huge connection queue. This applies only to the Sun/Oracle HotSpot JVM.

Security Settings
JVM parameters	Suggested value	Description
`-Dhttps.protocols`	`TLSv1.2`	Controls the protocols used for outbound HTTPS connections from AM. Specify one or more of the following values, separated by commas: TLSv1 TLSv1.1 TLSv1.2 TLSv1.3 This setting applies only to Sun/Oracle Java environments.
`-Dorg.forgerock.openam.ldap.secure.protocol.version`	`TLSv1.2`	Controls the protocol AM uses to connect to various external resources. Specify one or more of the following values, separated by commas: TLSv1 TLSv1.1 TLSv1.2 TLSv1.3

For -Dhttps.protocols, specify the protocol version(s) Java clients can use to connect to AM.

For -Dorg.forgerock.openam.ldap.secure.protocol.version, see Secure network communication for a list of external resources to which communication is affected.

Specify a single protocol if AM will only use that protocol when connecting to affected external resources. For example, a value of TLSv1.2 configures AM to only use the TLSv1.2 protocol to connect.

Specify a comma-separated list with multiple protocols if AM will use the most secure protocol supported by the external resources. For example, if you are using at least JDK 11 you could specify a value of TLSv1,TLSv1.1,TLSv1.2,TLSv1.3, which configures AM to attempt to use the TLSv1.3 protocol to connect to external configuration and user data stores. If a TLSv1.3 connection is not supported, AM attempts to use TLSv1.2 to connect, then TLSv1.1, and if still not supported, AM uses TLSv1.

Garbage Collection Settings
JVM parameters	Suggested value	Description
`-verbose:gc`		Verbose garbage collection reporting.
`-Xlog:gc*`	`-Xlog:gc=info:file=$CATALINA_HOME/logs/gc-info.log`	Logs detailed information about garbage collection. When using the `-Xlog:gc` option, you can also specify the level, and output file.
`-XX:+HeapDumpOnOutOfMemoryError`		Out of Memory errors generate a heap dump automatically.
`-XX:HeapDumpPath`	`$CATALINA_HOME/logs/heapdump.hprof`	Location of the heap dump.
`-XX:+PrintClassHistogram`		Prints a heap histogram when the JVM receives a SIGTERM signal.

AM 7.2.0

Tune JVM settings