HP XP P9500 Storage - Manual (Page 23)

Use the following formula. The ceil()value between the parentheses should be rounded up to
the nearest integer. LBA = Logical Block Address. The "Max. LBA" indicates the capacity of a
volume and is measured in blocks.
For OPEN-3, OPEN-8, OPEN-9, OPEN-E, OPEN-L, OPEN-K:
The number of cylinders = ceil(ceil(Max. LBA/96)/15)+1
For OPEN-V:
The number of cylinders = ceil(ceil(Max. LBA/512)/15)+1
To calculate the number of bitmap areas in each volume
For OPEN-3, OPEN-8, OPEN-9, OPEN-E, OPEN-L, OPEN-K:
The number of bitmap areas = ceil((number of cylinders x 15)/122,752)
The ceil() indicates that the value between the parentheses should be rounded up to the nearest
integer.
122,752 is the amount of differential data per bitmap area. The differential data is measured in
bits. If you are managing the differential data by cylinder, use the number of the cylinders instead
of the number derived from “number of cylinders x 15” to calculate the number of bitmap areas.
For OPEN-V: (when calculating the number of bitmap areas by using the number of cylinders that
is calculated by using the formula mentioned earlier).
The number of bitmap areas = ceil((number of cylinders x 15)/122,752)
If using OPEN-V and calculating the number of bitmap areas by using the number of cylinders
displayed in Remote Web Console windows, then use this formula:
The number of bitmap areas = ceil (((Number of cylinders /4) x
15)/122,752)
To calculate the maximum number of pairs that can be created
The maximum number of pairs you can create is defined by the following:
•
The number of bitmap areas required to create pairs (determined above).
•
The total number of bitmap areas of the storage system is 65,536.
Calculate the maximum number of pairs you can create using the following formula. Use the total
number of bitmap areas shown in the table above, and the required number of bitmap areas
calculated above.
The floor()indicates the value between the parentheses should be rounded down to the former
integer.
Maximum number of pairs = floor (the total number of bitmap areas in
the storage system / Number of bitmap areas)
The maximum number of pairs is limited to 32,768. If RAID Manager is used it is 32,767.
When the calculated maximum number of pairs exceeds the total number of LDEVs of the storage
system, and the total number of LDEVs of the storage system is less than 32,768, the total number
of LDEVs of the storage system becomes the maximum number of pairs.
Priority set for initial copy operations and scheduling order
For performing more initial copy operations than the setting value of the Maximum Initial Copy
Activities set on the System Option dialog box, the scheduling order (Priority) can be set for the
initial copy operations to be performed. This section explains the assignment of the scheduling
order of initial copy operations in cases where two sets of multiple initial copy operations are
performed.
An example is described in which four Continuous Access Synchronous pairs are created at the
same time in cases where the setting value of the Maximum Initial Copy Activities is 2. The Priority
which is set for the P-VOLs of Continuous Access Synchronous pairs is shown in the following table.
Planning volume pairs 23