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IBM Tivoli Identity Manager Performance Tuning Guide
1.3.1 Memory
All middleware components allow you to adjust how much memory they will use. When calculating how to
allocate memory to middleware components, keep these considerations in mind:
• Configuring middleware memory settings too high such that the total configured value exceeds
available physical memory can result in the operating system swapping memory out to disk. This
will result in extremely poor performance and should be avoided. After setting up or
changing the memory values for the middleware, monitor the memory and swap space used to
ensure that nothing is being swapped out to disk. If it is, adjust your memory settings to correct.
• A large part of the WebSphere Application Server’s memory usage is the JVM size. However, the
size of the JVM does not set an upper bound on the amount of memory that the WebSphere
Application Server may use. See the
IBM WebSphere Application Server section.
1.3.2 CPU
All the components of the IBM Tivoli Identity Manager product (IBM Tivoli Identity Manager application,
WebSphere Application Server, database server, and directory server) are CPU-intensive. Normally,
batch processes such as DSML feeds are less CPU intensive than interactive commands such as
changing passwords. Operations involving workflow, such as account creation, are very computationally
intensive, especially when customized workflow processes are enabled. zAAP processors, if available,
should be utilized in the z/OS instances supporting IBM Tivoli Identity Manager.
1.3.3 Disk space
Each of the middleware components uses different amounts of disk space for various purposes.
• WebSphere Application Server and the IBM Tivoli Identity Manager application use disk space
beyond their installation size because of log files (such as the
msg.log and trace.log files) and
WebSphere MQ queues. Adjust the number of archives and size of the
msg.log and trace.log
files in the enRoleLogging.properties file. Make sure that WebSphere MQ has enough disk space
for its processing logs (not error logs) to grow. The IBM Tivoli Identity Manager server pushes
many entries onto the queues during large provisioning changes, causing the queues to grow.
• IBM DB2 archive logs can consume a great deal of space for large transactions. For example,
automatically provisioning an IBM Tivoli Identity Manager account for 50k people resulted in 13.5
GB of space being used. Only 2.7 GB was for account storage (both inside the LDAP Server and
the historical logging in IBM DB2), the remainder, roughly 80%, was used by IBM DB2 archive
logs. Frequent purging of IBM DB2 archive logs may be required for busy systems.