5.4. Integrating a DLPAR operation into the application

The DLPAR operation can be integrated into the application using the following two methods:

• Script-based DLPAR event handling

  If the application is externally controlled to use a specific number of threads or to size its buffers, use this method. In order to facilitate this method, a new command, drmgr, is provided. The drmgr command is the central focal point of the dynamic logical partitioning function of AIX.

• API-based DLPAR event handling

  If the application is directly aware of the system configuration, and the application source code is available, use this method.

Applications can monitor and respond to various DLPAR events, such as a memory addition or processor removal, by utilizing these two methods. Although, at the high-level, both methods share the same DLPAR events flow explained in the following section, several key differences exist between these two methods.

One difference is that the script-based method externally reconfigures the application once a DLPAR event takes place, while the API-based method can be directly integrated into the application by registering a signal handler using the dr_reconfig system call, so that the process can be notified with the SIGRECONFIG signal when the DLPAR event occurs.