Hitachi Universal Replicator for z/OS User Guide: HP XP12000 Disk Array, HP XP10000 Disk Array, HP 200 Storage Virtualization System (T1778-96021, May 2011)

the number of pairs is applied to both the primary storage system and the secondary storage
system.
• The number of the required bitmap areas:
The number of bitmap areas to be used by all data volumes that form pairs can be calculated
out of the number of cylinders. If one pair of extended shared memories is used, the number
of bitmap areas that can be used in a disk subsystem is 11,605. If two pairs of extended
shared memories are used, the number of bitmap areas that can be used in a disk subsystem
is 28,671.
NOTE: If the calculated number of bitmap areas exceeds the total number of bitmap areas
in the disk subsystem, the number of pairs that can be created will be limited.
Use the following formula to calculate the number of bitmap areas to be used for each volume:
The number of bitmap areas = ( ((number of cylinders × 15) ÷ 122,752) )
The … symbols enclosing a value indicate that the enclosed value should be rounded up to
the nearest integer.
• The maximum number of pairs that can be created:
Use the following formula to calculate the maximum number of pairs that can be created:
Use this formula when one pair of extended shared cache memories is used:
◦ The maximum number of pairs
that you can create = (
(11,605/Number of bitmap areas) )
The … symbols enclosing a value indicate that the enclosed value should be rounded
up to the nearest integer.
◦ Use this formula when two pairs of extended shared cache memories are used:
The maximum number of pairs
that you can create = (
(28,671/Number of bitmap areas) )
The … symbols enclosing a value indicate that the enclosed value should be rounded
up to the nearest integer.
NOTE: If the calculated maximum number of pairs exceeds 16,384, the actual maximum
number of pairs is limited to 16,384.
Table 15 (page 44) illustrates the maximum number of pairs according to each emulation
type, when pairs are created without use of VLL volume.
“Maximum Number of Pairs According to Each Emulation Type, When Pairs Are Created Without
Use of VLL Volume” (page 44) illustrates the maximum number of pairs according to each emulation
type, when pairs are created without use of VLL volume.
Table 15 Maximum Number of Pairs According to Each Emulation Type, When Pairs Are Created
Without Use of VLL Volume
Maximum Number of Pairs
(Added Shared Memory: 2
pairs)
Maximum Number of Pairs
(Added Shared Memory: 1 pair)
Number of
Bitmap
Areas
Number of
Cylinders
Emulation
Type
16,38411,60513,3393380-3
16,38411,60511,7703380-E
16,38411,60518853380-J
16,38411,60512,6553380-K
44 Requirements and Restrictions for Universal Replicator z/OS Operations