Manage memory pools

Making sure that jobs get enough memory to complete efficiently is important. If too much memory is given to subsystem A and not enough to subsystem B, jobs in subsystem B might begin to run poorly. The following information describes the various tasks that are involved in managing memory pools.

• View memory pool information
  You can view information about the memory pools that are on your system by using iSeries™ Navigator or the character-based interface.
• Determine the number of subsystems using a memory pool
  Subsystems are allocated a certain percentage of memory to run jobs. It is important to know how many different subsystems are pulling from the same memory pool. After you know how many subsystems are submitting jobs to a pool and how many jobs are running in a pool, you might want to reduce resource contention by adjusting the size and activity level of the pool.
• Determine the number of jobs in a memory pool
  The iSeries™ Navigator provides you with a way to quickly display a list of jobs that are currently running in a memory pool.
• Determine in which pool a single job is running
  If you have a job that is not performing as you expect you might want to check the memory pool in which the job is running. To determine in which pool a single job is running, use iSeries™ Navigator or the character based interface.
• Manage tuning parameters for shared pools
  To manage tuning parameters for shared pools, use iSeries™ Navigator or character-based interface commands.
• Manage a pool's configuration
  To change a pool's size, activity level or paging option, use iSeries™ Navigator or character-based interface commands.
• Change memory pool size
  The size of a memory pool directly affects the amount of work that a subsystem can process. The more memory a subsystem has, the more work it can potentially complete. It is important that you monitor your system carefully before you start changing the parameters of your memory pools. You will also want to periodically recheck these levels, as some readjustment might need to be done.
• Create a private memory pool
  Private memory pools (also known as user-defined memory pools) can be used by IBM-supplied subsystems or by user-defined subsystems. You can define up to a maximum of 10 memory pool definitions for a subsystem. You create a private memory pool in the subsystem description.