Calculating The Number Of Bc Pairs If Luse Is Not Used; Calculating The Number Of Bc Pairs If Luse Is Used - HP StorageWorks XP10000 User Manual

Table 7 Number of differential tables used in OPEN-V (continued)
1
Capacity
Up to 1,811.2GB
Up to 1,826.1GB
Up to 1,841.1GB
Up to 1,856.1GB
Up to 1,871.0GB
Up to 1,886.0GB
Up to 1,901.0GB
Up to 1,915.9GB
Up to 1,930.9GB
1. 1 GB = 1024
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

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:
number of BC Pairs
Σ α ( ) { (
×
• is the required number of differential tables per pair (see
α ( )
• (number of BC pairs) is the number of BC pairs you want to create.
• 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.
β ( )
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:
1 10 + 193 20
×
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:
Σ Σ α ( ) [ { ( number of volumes that form LUSE volumes
×
• is the required number of differential tables for each volume that forms the LUSE volume.
α ( )
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.
• β ( ) is number of differential tables in the disk array.
20 Business Copy XP (BC) for the XP10000/XP12000
Differential Capacity
tables
121 Up to 2,305.1GB
122 Up to 2,320.1GB
123 Up to 2,335.1GB
124 Up to 2,350.0GB
125 Up to 2,365.0GB
126 Up to 2,380.0GB
127 Up to 2,394.9GB
128 Up to 2,409.9GB
129 Up to 2,424.9GB
3
Bytes
, where:
) } β ( )
≤
= 3870 13,652
× ≤
1
Differential
tables
154
155
156
157
158
159
160
161
162
.
) } ( number of BC pairs
×
1
Capacity
Up to 2,799.1GB
Up to 2,814.1GB
Up to 2,829.0GB
Up to 2,844.0GB
Up to 2,859.0GB
Up to 2,873.9GB
Up to 2,880.0GB
Table 4).
) ] β ( ) , where:
≤
Differential
tables
187
188
189
190
191
192
193
Table 4.