If you want to expand a pool for which data direct mapping is enabled, you must free up space in the pool. Make sure that the estimated capacity of free space is available before expanding the pool.
Use these mathematical formulas to estimate the capacity of free space required in the pool:
- Formula 1:
Required-free-space-for-a-pool-to-be-added-of-one-external-volume-of-the-data-direct-mapping-attribute [in MB] = (ceiling (pool-VOL-capacity [in MB] / 3,145,548 MB) * 4 pages * 42 MB) + ( ceiling (pool-VOL-capacity [in MB] / 42 MB) - floor (pool-VOL-capacity [in MB] / 42 MB) ) * 42MB
- Formula 2:
Required-capacity-of-pool-VOL-with-system-area-in-one-pool-of-a-data-direct-mapping-attribute [in MB] = Total-of-calculated-values-by-the-Formula-1-for-each-volume + Management area (4200) [in MB] + 42 [in MB]
where
- ceiling: The value enclosed in ceiling( ) must be rounded up to the nearest whole number.
- floor: The value enclosed in floor( ) must be rounded down to the nearest whole number.
A V-VOL with data direct mapping attribute uses these capacities:
- Mapped capacity uses multiples of 42 MB in the capacity of the pool volume as well as the capacity for one page (the area of the capacity other than multiples of 42 MB).
- Control information (168 MB is used per 3,145,548 MB).
The pool-VOL with the system area contains the one page capacity and control information.