Items |
Requirements |
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Pool capacity |
Calculate pool capacity using this formula: Capacity of the pool (MB) = total-number-of-pages * 42 - 4200. 42 in the formula is size (MB) for one page and 4200 in the formula is the management area size of the pool-VOL with System Area. Total number of pages = Σ(floor(floor(pool-VOL number of blocks / 512) / 168)) for each pool-VOL. floor( ): Truncates the value calculated from the formula in parentheses after the decimal point (that is, round down to nearest whole number). Because pools are limited to 1024 pool-VOLs, and pool-VOLs (LDEVs) are limited to 2.99TiB when created on internal storage (4 TiB when external), pools made from internal pool-VOLs are limited to 2.99PiB. The minimum and maximum capacity sizes for one pool range from 3.9 GB to 4.0 PB. The maximum capacity sizes of all pools in a storage system are as follows:
If you operate a pool without monitoring the free space, then ensure that the total V-VOL capacity remains smaller than the pool capacity. |
Maximum number of pool-VOLs | From 1 to 1,024 volumes (per pool). A volume can be registered as a pool-VOL to one pool only. |
Maximum number of pools | For a pool with compression accelerator enabled, see the tables that follow this one. The largest number of pools is 64. Assign a pool number in the range 0~63 as the identifier. |
Increasing capacity | You can increase pool capacity dynamically by adding pool-VOLs. The capacity is expanded by the parity group. |
Reducing capacity | You can reduce pool capacity dynamically by removing pool-VOLs. |
Deleting | You can delete pools that are not associated with any of the following items:
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Subscription limit | 0 through 65534 (%). You can set the subscription limit to Unlimited by leaving this field blank. Set the subscription limit to Unlimited when you create the pool that contains virtual volumes (V-VOLs) with capacity saving enabled. |
Thresholds |
If the pool used-capacity is equal to or greater than the warning threshold or the depletion threshold, a service information message (SIM) is issued by the storage system. Thresholds cannot be defined for a pool with data direct mapping enabled. |
Data allocation unit | 42 MB. The 42-MB page corresponds to a 42-MB continuous area of the V-VOL. Pages are allocated for the pool volumes only when data has been written to the area of the V-VOL. |
Maximum number of pools with capacity saving enabled and the maximum capacity of the total pool volumes
These tables indicate the maximum capacity of the total pool volumes and the number of pools that can be created.
VSP One B24
Added shared memories | Maximum capacity of the total pool volumes for one pool (PB) | Number of pools that can be created |
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Base | 4.4 | 64 |
VSP One B26
Added shared memories | Maximum capacity of the total pool volumes for one pool (PB) | Number of pools that can be created |
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Base | 4.4 | 64 |
Extension 1 | 8.05 | 64 |
VSP One B28
Added shared memories | Maximum capacity of the total pool volumes for one pool (PB) | Number of pools that can be created |
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Base | 4.4 | 64 |
Extension 1 | 8.05 | 64 |
Extension 2 | 12.5 | 64 |