Sun OpenSSO Enterprise 8.0 Performance Tuning Guide



Specifies a percentage value how much of the machine's available memory will be used by OpenSSO Enterprise.



Sample Values:

0 to 100

Default Value:


Additional Information:

Do not modify this percentage unless tests show significant improvement in performance.

OpenSSO Enterprise currently recommends at least 1 GB of RAM in deployment. OpenSSO can use a maximum of 4GB for 32-bit JRE. This is the per-process address space limit for 32-bit applications.

When you set AMTUNE_PCT_MEMORY_TO_USE to 100, the maximum space allocated for OpenSSO is the lesser of 4GB and 100% of available RAM for 32-bit JRE.

When you set AMTUNE_PCT_MEMORY_TO_USE to 0, OpenSSO is configured to use 256MB RAM.

This value is the driving force in tuning OpenSSO. The following values are derived from this setting:

JVM memory use

Heap and new generation sizes.

Thread pool sizes

Web Server thread pool and OpenSSO Enterprise authentication, user and service/configuration data store LDAP connection pools and session notification thread pool.

Session entries

Maximum number of session entries.

For 64-bit JRE, the amtune tool limits the initial heap size (-Xms) to 12 GB for Web Server 7 and Application Server 9.1/Glassfish v2, although it can be increased manually to a bigger heap size, if the Solaris operating system has at least twice as much virtual memory (swap space) as the desired initial JRE heap size. There is no limit for the maximum heap size (-Xmx).

Using 64-bit JRE, the user session cache size and number of sessionsare calculated by the amtune tool, and can be many times of those calculated in case for 32-bit JRE, depending on the available memory. Be sure to review these numbers and determine whether or not they are appropriate .