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Capacity
1
Differen-
tial tables
Capacity
1
Differen-
tial tables
Capacity
1
Differen-
tial tables
Up to 1,856.1GB
124
Up to 2,350.0GB
157
Up to 2,844.0GB
190
Up to 1,871.0GB 125 Up to 2,365.0GB 158 Up to 2,859.0GB 191
Up to 1,886.0GB 126 Up to 2,380.0GB 159 Up to 2,873.9GB 192
Up to 1,901.0GB 127
Up to 2,394.9GB
16 0 Up t o 2,88 0.0 G B 193
Up to 1,915.9GB 128
Up to 2,409.9GB
161
Up to 1,930.9GB 129
Up to 2,424.9GB
162
1
1GB=1024
3
Bytes
If you intend to create pairs with volumes of different emulation types, the maximum number of pairs you
can create depends on the following conditions.
NOTE:
For more information about calculating total number of differential tables per pair, see Table 3.
Calculating the number of BC pairs if LUSE is not used
Use the following equation to calculate whether the desired number of BC pairs can be created:
Σ{(α) x (number of BC Pairs)} ≤ (Β), where:
• (α) is the required number of differential tables per pair (see Table 3).
• (number of BC pairs) is the number of BC pairs you want to create.
• (Β) is number of differential tables in the disk array.
•(Β) = 13,652 when additional shared memory for differential tables is not installed.
•(Β) = 30,718 when additional shared memory for differential tables is installed.
For example, if you create 10 pairs of OPEN-3 volumes and 20 pairs of OPEN-V volumes in a disk array
that does not have additional shared memory for differential tables, use the following equation:
1x10+193x20=3870≤ 13 , 652
Since 3,870 is less than 13,652, 10 pairs of OPEN-3 volumes and 20 pairs of OPEN-V volumes can
be created.
NOTE:
When the emulation type is OPEN-3, and the capacity of the volume is 2,403,360 KB, the number of
differential tables required for a pair is 1. When the emulation type is OPEN-V, and the capacity of the
volume is 3,019,898,880 KB, the number of differential tables required for a pair is193.
Calculati
ng the number of BC pairs if LUSE is used
Use the fol
lowing equation to calculate whether the desired number of BC pairs can be created:
Σ[Σ{(α)x(
number of volumes that form LUSE volumes)} x (number of BC pairs)] ≤ (Β), where:
• (α) is the required number of differential tables for each volume that forms the LUSE volume.
When you use LUSE volumes to create a BC pair, every volume that forms the LUSE volume uses the
differen
tial tables as a pair. For example, if you create a BC pair by using LUSE volumes that are
created b
y combining two OPEN-V volumes, you need differential tables for two OPEN-V pairs.
• (Β) is number of differential tables in the disk array.
•(Β) = 13,652 when additional shared memory for differential tables is not installed.
20
Business Copy XP (BC) for the Array