Db2 internal resource lock manager

The Db2 internal resource lock manager (IRLM) is both a separate subsystem and an integral component of Db2. IRLM works with Db2 to control access to your data.

IRLM is shipped with Db2, and each Db2 subsystem must have its own instance of IRLM. You cannot share IRLM between Db2 subsystems or between Db2 and IMS subsystems. IRLM is also shipped with IMS. If you run a Db2 data sharing group, an IRLM group corresponds to that data sharing group.

IRLM works with Db2 to serialize access to your data. Db2 requests locks from IRLM to ensure data integrity when applications, utilities, and commands attempt to access the same data.

Recommendation: Always run with the latest level of IRLM.

IRLM requires some control and monitoring. The external interfaces to the IRLM include:

Installation: Install IRLM when you install Db2. Consider that locks take up storage, and adequate storage for IRLM is crucial to the performance of your system.
Another important performance item is to set WLM goals to maximize response time and execution velocity for the IRLM address space above all the other Db2 address spaces.
Commands: Some IRLM-specific z/OS® commands enable you to modify parameters, display information about the status of the IRLM and its storage use, and start and stop IRLM.
Tracing: The Db2 trace facility enables you to trace lock interactions.
You can use z/OS trace commands or IRLMPROC options to control diagnostic traces for IRLM. You normally use these traces under the direction of IBM® Support.