Installation manual

Performance and Scalability Recommended JVM Tuning Set
Release Notes for Release 9.1 Service Pack 3 (9.1.30151.0) Page 12
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Behind the
Blackboard.
Recommended JVM Tuning Set
For every Service Pack release, the Blackboard Performance Engineering team spends many
hours studying the transactional and systemic performance of Blackboard Learn and whether
particular tuning sets will have a positive or negative impact on performance or scalability.
This section provides the recommended Java Virtual Machine (JVM) tuning set as executed in
the Blackboard Performance Engineering laboratory against Release 9.1 Service Pack 2.
Customers are strongly encouraged to deploy their application environments in a 64-bit
configuration using the recommended 4GB, 8GB, or larger tuning set.
Blackboard recommends using the following tuning set for 8GB JVMs (64-bit) on Windows, Linux,
and Solaris systems using Java 1.6. These recommended settings can be managed within the
bb-config.properties file or wrapper.conf file:
-Xms8192m –Xmx8192m -XX:NewSize=2048m -XX:MaxNewSize=2048m
-XX:SurvivorRatio=4 -XX:+UseConcMarkSweepGC -XX:+UseParNewGC
-XX:+UseTLAB -XX:PermSize=256m -XX:ParallelCMSThreads=2
-XX:ParallelGCThreads=4 -XX:+PrintVMOptions -XX:+PrintGCDetails
-XX:+PrintGCTimeStamps -XX:+PrintGCTaskTimeStamps
-XX:+PrintCommandLineFlags -XX:+PrintGCApplicationStoppedTime
-XX:+PrintGCApplicationConcurrentTime
-Xloggc:<blackboard_directory>/logs/tomcat/gc.log
When using a 4GB heap size, change the following parameter values in the recommended tuning
set:
-Xms4096m -Xmx4096m -XX:NewSize=1024m -XX:MaxNewSize=1024m
Guidance for 32-bit configurations is also included below, however, to achieve the best
performance and scalability, 32-bit environments are not recommended for use in production
situations. 32-bit Windows and Red Hat Enterprise Linux deployments are limited to JVM sizes no
greater than 1.7GB of addressable memory. This consists of the main heap area (Old and New
Space) plus the permanent space. For 32-bit configurations with a 1.4GB heap size, Blackboard
recommends changing the following parameter values in the recommended tuning set:
-Xms1400m –Xmx1400m -XX:NewSize=350m -XX:MaxNewSize=350m
Understanding the Settings
Additional performance tuning may be required for certain configurations depending on how much
memory is available and what other processes are running. Some of the parameters below can
be changed to match your particular environment and improve overall performance.