Working with ASP trace and ASP balance

The three types of auxiliary storage Pool (ASP) balancing actions that you can choose.

  • Capacity balance
  • Hierarchical storage management (HSM) balance
  • Usage balance

The balancing actions use the results of previous ASP traces to determine disk unit usage. Therefore, an ASP balance is more effective if you run an ASP trace first.

The following are restrictions and considerations for balancing actions:

  • The usage balance uses the results of previous ASP traces to determine the disk unit usage. Trace an ASP before you run a usage balance.
  • The HSM balance uses the results of previous ASP traces to determine the disk unit usage. Trace an ASP before you can run an HSM balance.
  • The HSM balance requires a mixture of compressed and non-compressed disk units in the ASP.
  • The system experiences degraded performance during the Trace activity and Balance activity.
  • You can use the Trace and Balance functions in only ASPs that contain more than one disk unit.
  • You can add an unconfigured disk unit to the configuration during the time a Trace is running. In this case, the system automatically includes the newly configured disk unit in the trace activity.
  • You can run a single trace activity or balance activity only at a specific time to an ASP.
  • The amount of improvement in system throughput that is achieved by running the balance depends on many of the following factors.
    • The amount of main storage.
    • The number of processors.
    • The level of activity on the system.
    • The amount of cache in the storage subsystem.
    • Start of changeThe quantity of disk units under each I/O processor in each storage subsystem.End of change