HP XP Business Copy Software - Manual (Page 20)

20 Business Copy XP (BC) for the XP10000/XP12000
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 4 .
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:
, where:
• is the required number of differential tables per pair (see Table 4 ).
• (number of BC pairs) is the number of BC pairs you want to create.
• is number of differential tables in the disk array.
• = 13,652 when additional shared memory for differential tables is not installed.
• = 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:
.
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.
Calculating the number of BC pairs if LUSE is used
Use the following equation to calculate whether the desired number of BC pairs can be created:
, where:
• 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
differential tables as a pair. For example, if you create a BC pair by using LUSE volumes that are
created by combining two OPEN-V volumes, you need differential tables for two OPEN-V pairs.
• is number of differential tables in the disk array.
Up to 1,811.2GB 121 Up to 2,305.1GB 154 Up to 2,799.1GB 187
Up to 1,826.1GB 122 Up to 2,320.1GB 155 Up to 2,814.1GB 188
Up to 1,841.1GB 123 Up to 2,335.1GB 156 Up to 2,829.0GB 189
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 160 Up to 2,880.0GB 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. 1 GB = 1024 3 Bytes
Table 7 Number of differential tables used in OPEN-V (continued)
Capacity 1 Differential
tables
Capacity 1 Differential
tables
Capacity 1 Differential
tables
Σ α ( ) number of BC Pairs ( ) × { } β ( ) ≤
α ( )
β ( )
β ( )
β ( )
1 10 193 20 Ч + Ч 3870 13,652 ≤ =
Σ Σ α ( ) number of volumes that form LUSE volumes ( ) × { } number of BC pairs ( ) × [ ] β ( ) ≤
α ( )
β ( )