Change Shared Storage Pool (CHGSHRPOOL)
| Where allowed to run: All environments (*ALL) Threadsafe: No |
Parameters Examples Error messages |
The Change Shared Storage Pool (CHGSHRPOOL) command changes the size, activity level, or tuning values for a shared pool. The only authority required to change a shared pool is authority to the command. When increasing the size of the shared pool, the change takes effect immediately if the shared pool is active (being used by a subsystem, by an active job, or for data) and the storage is available. If the shared pool is not active, the change takes effect when a subsystem is started using the shared pool.
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Parameters
| Keyword | Description | Choices | Notes |
|---|---|---|---|
| POOL | Pool identifier | *MACHINE, *BASE, *INTERACT, *SPOOL, *SHRPOOL1, *SHRPOOL2, *SHRPOOL3, *SHRPOOL4, *SHRPOOL5, *SHRPOOL6, *SHRPOOL7, *SHRPOOL8, *SHRPOOL9, *SHRPOOL10, *SHRPOOL11, *SHRPOOL12, *SHRPOOL13, *SHRPOOL14, *SHRPOOL15, *SHRPOOL16, *SHRPOOL17, *SHRPOOL18, *SHRPOOL19, *SHRPOOL20, *SHRPOOL21, *SHRPOOL22, *SHRPOOL23, *SHRPOOL24, *SHRPOOL25, *SHRPOOL26, *SHRPOOL27, *SHRPOOL28, *SHRPOOL29, *SHRPOOL30, *SHRPOOL31, *SHRPOOL32, *SHRPOOL33, *SHRPOOL34, *SHRPOOL35, *SHRPOOL36, *SHRPOOL37, *SHRPOOL38, *SHRPOOL39, *SHRPOOL40, *SHRPOOL41, *SHRPOOL42, *SHRPOOL43, *SHRPOOL44, *SHRPOOL45, *SHRPOOL46, *SHRPOOL47, *SHRPOOL48, *SHRPOOL49, *SHRPOOL50, *SHRPOOL51, *SHRPOOL52, *SHRPOOL53, *SHRPOOL54, *SHRPOOL55, *SHRPOOL56, *SHRPOOL57, *SHRPOOL58, *SHRPOOL59, *SHRPOOL60 | Required, Positional 1 |
| SIZE | Storage size | Single values: *SAME, *NOSTG Other values: Element list |
Optional, Positional 2 |
| Element 1: Number of units | Integer | ||
| Element 2: Unit of measure | *KB, *MB | ||
| ACTLVL | Activity level | Integer, *SAME, *DATA | Optional, Positional 3 |
| PAGING | Paging option | *SAME, *FIXED, *CALC | Optional, Positional 4 |
| TEXT | Text 'description' | Character value, *SAME, *BLANK | Optional |
| MINFAULT | Minimum page faults | Decimal number, *SAME, *DFT | Optional |
| JOBFAULT | Per thread page faults | Decimal number, *SAME, *DFT | Optional |
| MAXFAULT | Maximum page faults | Decimal number, *SAME, *DFT | Optional |
| PTY | Priority | 1-14, *SAME, *DFT | Optional |
| MINPCT | Minimum size % | 0.0-100.0, *SAME, *DFT | Optional |
| MAXPCT | Maximum size % | 0.0-100.0, *SAME, *DFT | Optional |
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Pool identifier (POOL)
Specifies the shared pool being changed. More information about storage pools is in the Work Management and the Backup and Recovery topics in the IBM i Information Center at http://www.ibm.com/systems/i/infocenter/.
This is a required parameter.
- *MACHINE
- The machine pool used for Licensed Internal Code is changed. Only the size can be changed for the machine pool. This is the same as using the Change System Value (CHGSYSVAL) command to change the QMCHPOOL system value.
- *BASE
- The base pool is changed. Only the activity level can be changed for the base pool. This is the same as using the CHGSYSVAL command to change the QBASACTLVL system value.
- *INTERACT
- The shared pool for interactive work is changed.
- *SPOOL
- The shared pool used for spooled writers is changed.
- *SHRPOOLnn
- A general-purpose shared pool is changed. There are sixty general-purpose shared pools, identified by special values *SHRPOOL1 to *SHRPOOL60.
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Storage size (SIZE)
Specifies the size of the storage pool. This is the amount of main storage that can be used by the pool. A value of at least 256 kilobytes must be specified for the storage size. The second element of this parameter specifies whether the size is expressed in kilobytes or megabytes.
Single values
- *SAME
- The size does not change.
- *NOSTG
- No storage or activity level is defined for the pool. A pool cannot be changed to *NOSTG if it is being used by an active subsystem or active job or if the pool has reserved storage.
Element 1: Number of units
- integer
- Specify the size of the storage pool.
Note: Changes to the size of a pool may require pages to be written to auxiliary storage. The time required for the system to complete a large change may be greater than your default wait time. If this occurs, message CPF1001 (Wait time expired for system response.) is issued, even though the change completes.
Element 2: Unit of measure
- *KB
- The size is specified in kilobytes (1024 byte units).
- *MB
- The size is specified in megabytes (1048576 byte units).
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Activity level (ACTLVL)
Specifies the maximum number of threads that can run at the same time in the pool.
- *SAME
- The activity level does not change.
- *DATA
- No threads can run in the pool. It is only used for data. A pool cannot be changed to or from *DATA if it is being used.
- integer
- Specify the activity level for the pool.
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Paging option (PAGING)
Specifies the paging option associated with the pool. The paging option determines whether the system dynamically adjusts the paging characteristics for the storage pool for optimum performance. Pools with *DATA activity level are not dynamically adjusted by the system.
- *SAME
- The value does not change.
- *FIXED
- The system default values are used. The system does not dynamically adjust the paging characteristics for the storage pool.
- *CALC
- The system dynamically adjusts the paging characteristics for the storage pool to ensure optimum performance.
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Text 'description' (TEXT)
Specifies the text that briefly describes the shared pool.
- *SAME
- The text does not change.
- *BLANK
- No text is specified.
- character-value
- Specify no more than 50 characters of text, enclosed in apostrophes.
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Minimum page faults (MINFAULT)
Specifies the minimum page faults per second to use as a guideline for this storage pool. This value is used by the system if the QPFRADJ system value is set to 2 or 3 (automatic adjustment). Pools with *DATA activity level are not automatically adjusted by the system.
- *SAME
- The value does not change.
- *DFT
- The minimum faulting rate guideline is set to the system default value for this pool.
- decimal-number
- Specify the minimum page faults per second to use for the paging guideline for this pool.
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Per thread page faults (JOBFAULT)
Specifies the page faults per second for each active thread to use as a guideline for this storage pool. Each job is comprised of one or more threads. A thread is counted as active when it uses CPU resource. This value is used by the system if the QPFRADJ system value is set to 2 or 3 (automatic adjustment). Pools with *DATA activity level are not automatically adjusted by the system.
- *SAME
- The value does not change.
- *DFT
- The guideline for the page faults per second for each active thread is set to the system default value for this pool.
- decimal-number
- Specify the page faults per second for each active thread to use for the paging guideline for this pool.
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Maximum page faults (MAXFAULT)
Specifies the maximum page faults per second to use as a guideline for this storage pool. This value is used by the system if the QPFRADJ system value is set to 2 or 3. Pools with *DATA activity level are not automatically adjusted by the system.
- *SAME
- The value does not change.
- *DFT
- The maximum faulting rate guideline is set to the system default value for this pool.
- decimal-number
- Specify the maximum page faults per second to use for the paging guideline for this pool.
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Priority (PTY)
Specifies the priority of this pool relative to the priority of the other storage pools. The valid range for priority is 1-14, where 1 is the highest priority and 14 is the lowest priority. This value is used by the system if the QPFRADJ system value is set to 2 or 3. Pools with *DATA activity level are not automatically adjusted by the system.
- *SAME
- The value does not change.
- *DFT
- The storage pool priority is set to the system default value for this pool.
- 1-14
- Specify the priority of the storage pool.
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Minimum size % (MINPCT)
Specifies the minimum amount of storage to allocate to this storage pool (as a percentage of total main storage). This value is used by the system if the QPFRADJ system value is set to 2 or 3. Pools with *DATA activity level are not automatically adjusted by the system.
- *SAME
- The value does not change.
- *DFT
- The minimum pool size is set to the system default value for this pool.
- 0.0-100.0
- Specify a percentage of total main storage to use as a minimum size for this storage pool.
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Maximum size % (MAXPCT)
Specifies the maximum amount of storage to allocate to this storage pool (as a percentage of total main storage). The maximum size of a pool is determined by this percentage and the amount of storage allocated to the other active pools. This value is used by the system if the QPFRADJ system value is set to 2 or 3. Pools with *DATA activity level are not automatically adjusted by the system.
- *SAME
- The value does not change.
- *DFT
- The maximum pool size is set to the system default value for this pool.
- 0.0-100.0
- Specify a percentage of total main storage to use as a maximum size for this storage pool.
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Examples
Example 1: Changing the Size of the Interactive Pool
CHGSHRPOOL POOL(*INTERACT) SIZE(4200)
ACTLVL(*SAME) PAGING(*SAME)
This command changes the size of the interactive pool to 4200 kilobytes. The activity level and paging option remain the same.
Example 2: Changing a Pool to Only be Used for Data
CHGSHRPOOL POOL(*SHRPOOL5) SIZE(80000)
ACTLVL(*DATA) TEXT('Data pool for LINUX1 NWSD')
This command changes Shared Pool 5 into a data pool with a size of 80000 kilobytes. The activity level will prevent any jobs from running in the pool.
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Error messages
*ESCAPE Messages
- CPF1001
- Wait time expired for system response.
- CPF1076
- Specified value not allowed for system value &1.
- CPF1078
- System value &1 not changed.
- CPF113A
- Sum of MINFAULT and JOBFAULT parameters exceeds MAXFAULT parameter.
- CPF113B
- Minimum size percentage exceeds maximum size percentage.
- CPF113C
- Private pool attributes not changed.
- CPF115D
- Shared pool &1 not changed.
- CPF1157
- Shared pool &1 not changed to *NOSTG.
- CPF1165
- Specified parameter not allowed for *MACHINE pool.
- CPF1166
- Specified parameter not allowed for *BASE pool.
- CPF1167
- ACTLVL not specified for pool &1.
- CPF1225
- SIZE not specified for pool &1.
- CPF1831
- User not authorized to change system value &1.
- CPF1864
- User not authorized to change system value &1.
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