CL Command Reference - STRASPBAL
CL Command List > STRASPBAL Reference
Description:
The Start ASP Balance (STRASPBAL) command allows the user to start the auxiliary storage pool (ASP) balancing function for one or more ASPs. Four types of ASP balancing can be started:
1. Capacity balancing - The data on all the units within the ASP will be balanced so each unit has an equal percentage of used and unused space. This is useful when new units are added to an ASP. Instead of having several units with the majority of the data and several new ones with no data, the user can spread the data evenly across all the units.
2. Usage balancing - The ¡¯low¡¯ use data on each ¡¯low¡¯ utilized unit in the ASP is redistributed to balance future use of the arm utilization of each unit within the specified ASP. *USAGE balancing cannot be done until the trace controlled by the Trace ASP Balance (TRCASPBAL) command has collected usage statistics. The TRCASPBAL command starts the trace function that will identify the ¡¯high¡¯ and ¡¯low¡¯ use data on each unit. After the usage balance activity has run to completion, the trace information will be cleared. Usage balancing is useful when the ASP contains large capacity disk units.
3. Hierarchical Storage Management (HSM) balancing - The ¡¯high¡¯ use and ¡¯low¡¯ use data on each unit in the ASP is redistributed so that the ¡¯high¡¯ use data resides on high performance units and the ¡¯low¡¯ use data resides on low performance units. The ASP being balanced in this manner must contain the correct mixture of slow and fast units to perform this type of balance. This allows the ¡¯low¡¯ use data on the high performance units to be moved to low performance units. Data that is ¡¯high¡¯ use that resides on slow units will be moved to the fast disk units. HSM balancing cannot be done until the trace controlled by the Trace ASP Balance (TRCASPBAL) command has collected usage statistics. The TRCASPBAL command starts the trace function that will identify the ¡¯high¡¯ and ¡¯low¡¯ use data on each unit. After the HSM balance activity has run to completion, the trace information will be cleared. HSM balancing is useful when the ASP contains compressed disk units.
4. Move data from units - This option can be used to reduce the down time associated with removing a disk unit. A unit that is scheduled for removal can be marked to end allocations by specifying UNIT(unit-number) and TYPE(*ENDALC). This will keep new allocations away from this unit. For all units marked *ENDALC, specifying TYPE(*MOVDTA) will move data from the marked units to other units in the same ASP. To resume allocations for units marked *ENDALC, specify UNIT(unit-number) and TYPE(*RSMALC). New allocations will once again be allowed to this unit. The Check ASP Balance (CHKASPBAL) command can be used to determine which units are currently marked *ENDALC.
The user may specify a time limit that the function is to run for each ASP being balanced or the balance can be set to run to completion. If the balance function needs to be ended, use the End ASP Balance (ENDASPBAL) command. A message will be sent to the system history (QHST) log when the balancing function is started for each ASP. A message will also be sent to the QHST log when the balancing function completes or is ended.
If the balance function is run for a few hours and then stopped, it will continue from where it left off when the balance function restarts. This allows the balancing to be run during off hours over a several day period.
Restrictions:
. You must have all object (*ALLOBJ) special authority to run this command.
Examples:
Example 1: Starting ASP Balancing for ASP 1
STRASPBAL ASP(1) TIMLMT(*NOMAX) TYPE(*CAPACITY)
This command starts the *CAPACITY ASP balance function for ASP 1. The balance function will run until the capacity for each of the units has been balanced.
Example 2: Starting ASP Balancing with a Time Limit
STRASPBAL ASP(*ALL) TIMLMT(60) TYPE(*USAGE)
This command starts the *USAGE ASP balance function for the system ASP and each configured basic ASP for which the TRCASPBAL command has been run. Each balance function will have a time limit of sixty minutes. After sixty minutes, any balance functions which have not completed will be ended.
Example 3: Starting ASP Balancing for an ASP Device
STRASPBAL ASPDEV(MYASP1) TIMLMT(*NOMAX) TYPE(*CAPACITY)
This command starts the *CAPACITY ASP balance function for the ASP device named MYASP1. The balance function will run until complete.
Example 4: Preparing to Remove Units
STRASPBAL UNIT(11 12 13) TYPE(*ENDALC)
STRASPBAL TYPE(*MOVDTA)
The first command marks units 11, 12 and 13 to no longer receive new allocations. The second command begins to move data off the marked units. It is recommended that the *MOVDTA ASP balancing function be done during an off-peak time.