4 total number of differential tables per pair – HP XP Business Copy Software User Manual
Page 17
Business Copy XP user guide for the XP10000/XP12000
17
Calculating the number of differential tables for one BC pair
When you create a BC pair, the number of required differential tables changes according to the emulation
type of the volumes. Use the equations in
to calculate the total number of differential tables per
pair.
Table 4
Total number of differential tables per pair
Emulation type
Equation
OPEN-3
Total number of differential tables per pair =
(X): Volume capacity (KB)
1,2
(Y): Number of control cylinders associated with the emulation type (see
)
(Z): Number of slots that can be managed by a differential table (61,312)
NOTE:
Round the result of the calculation up to the nearest whole number.
For example, if the volume’s emulation type is OPEN-3, and it is not a custom volume, the
volume capacity (X) is the default volume size, 2,403,360 KB, and total number of differential
tables is calculated as follows:
When you round to the nearest whole number, the result is 1. Therefore, the total number of
differential tables for a pair is 1 when the emulation type is OPEN-3.
1. If the selected volume is a CVS (custom volume size) volume, use the capacity of the custom volume instead of the default volume
capacity for the emulation type. Since the OPEN-L emulation type does not support custom volume operations, you must use the
default volume capacity of OPEN-L for X.
2. 1 KB equals 1024 bytes.
OPEN-8
OPEN-9
OPEN-E
OPEN-L
OPEN-V
Total number of differential tables per pair =
(X): Volume capacity (KB)
2
(Z): Number of slots that can be managed by a differential table (61,312)
NOTE:
Round the result of the calculation up to the nearest whole number.
For example, if the volume capacity (X) is the maximum OPEN-V volume capacity of
3,019,898,880 KB, the total number of differential tables is calculated as follows:
When you round up to the nearest whole number, the result is 193. Therefore, the total number
of differential tables for a pair is 193 when the emulation type is OPEN-V.
Table 5
Number of control cylinders according to emulation types
Emulation type
Number of control cylinders
OPEN-3
8 (5,760 KB)
OPEN-8
27 (19,440 KB)
OPEN-9
OPEN-E
19 (13,680 KB)
OPEN-L
7 (5,040 KB)
OPEN-V
0 (0 KB)
X 48
÷
(
)
Y 15
×
(
)
+
[
]
Z
ч
2,403,360 48
ч
(
)
8 15
Ч
(
)
+
[
]
61,312
ч
0.81860
=
X 256
÷
(
)
Z
( )
ч
3,019,898,880 256
ч
(
)
61,312
ч
192.40084
=