HP P9000 for Compatible FlashCopy Mirroring User Guide (AV400-96388, October 2011)

When you round up 2.45379 to the nearest whole number, it becomes 3. Therefore, the total
number of the resources to be used for one relationship is 6 when emulation type is 3390-3.
When volumes that differ in the emulation type and capacity are, the number of relationships that
can be established is determined according to the following condition.
NOTE: For details about the calculation of the total number of the resources to be used per a
relationship, see the expression described above.
The maximum number of relationships that can be established is the largest number that meets the
equation, Σ(α) ≤ (β), where:
Σ(α) means the total number of resources used per a relationship, and
(β) means the total number of resources available in the storage system.
(β) = 26,176 or 104,768 or 209,600.
For details, see Table 17 (page 29).
Establishing relationships by dataset copying
To establish relationships between extents, the number of required resources is the same as the
number of resources used per relationship, provided that no extents in the same volume overlap.
If the extents used for establishing the relationships overlap, the number of resources required to
establish the relationships is the number of resources to be used multiplied by the number of extents
that overlap.
The following figures show the different cases of dataset copying when the extents overlap or do
not overlap. For information about the calculation example of the used resources, see Table 19 (page
33).
Figure 17 Copying data in two extents that do not overlap (One T-VOL)
Figure 18 Copying data in two extents that do not overlap (Two T-VOLs)
Calculating the maximum number of Compatible FlashCopy relationships 31