A pool is a set of volumes reserved for storing Dynamic Provisioning write data.
The following table lists and describes the requirements and specifications for pools.
|
Items |
Requirements and specifications |
|---|---|
| Pool capacity | Calculate pool capacity using this formula: Capacity of the pool (MB) = total-number-of-pages * 38 - 3800. 3800 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 / 116) / 672)) for each pool-VOL. where
The minimum capacity for a single pool is 8 GB. The maximum capacity for a single pool is as follows:
However, the upper limit of total capacity of all pools is 15.0 PB on each storage system if shared memory is installed. |
| 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 | Up to a total of 128 pools per storage system. The 128 pools include these pool types:
Pool IDs (0 to 127) are assigned as pool identifiers. |
| Increasing capacity | You can increase pool capacity dynamically. Best practice is to add pool-VOLs to increase capacity by one or more parity groups. |
| Reducing capacity | You can reduce pool capacity by removing pool-VOLs. |
| Deleting | You can delete pools that are not associated with any DP-VOLs or with any Thin Image Advanced pairs or Thin Image Advanced snapshot data. |
| Subscription limit | 0 through 65534 (%). You can set the subscription limit to Unlimited by leaving this field blank. |
| 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 | 38 MB The 38-MB page corresponds to a 38-MB continuous area of the DP-VOL. Pages are allocated for the pool volumes only when data has been written to the area of the DP-VOL. |