Working with ASP trace and ASP balance

Here are the three types of balancing action 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 will be more effective if you perform an ASP trace first.

The following restrictions and considerations:

• The usage balance uses the results of previous ASP traces to determine the disk unit usage. You must perform an ASP trace before you run a usage balance.
• The HSM balance uses the results of previous ASP traces to determine the disk unit usage. You must perform an ASP trace before you can run a HSM balance.
• The HSM balance requires a mixture of compressed and non-compressed disk units in the ASP.
• The system will experience degraded performance during the Trace activity and Balance activity.
• You can only use the Trace and Balance functions in Auxiliary Storage Pools which contain more than one disk unit.
• You can add a nonconfigured disk unit to the configuration during the time a Trace is running. In this case the system will automatically include the newly configured disk unit in the trace activity.
• You can only run a single trace activity or balance activity at a given time to an ASP.
• The amount of improvement in system throughput that is achieved by running the balance is dependent on many factors. This includes some of the following items.
  • The amount of main storage.
  • The number of processors.
  • The level of activity running on the system.
  • The amount of cache in the storage subsystem.
  • The quantity of disk arms under each I/O processor in each storage subsystem.