HP StorageWorks XP Remote Web Console Software - Manual (Page 65)

Calculating the Maximum Number of Version 2 Relationships
Version 2 can establish up to 1,048,575 relationships. However, Version 2 may not be able to
establish up to 1,048,575 relationships depending on the number of resources required for the
copy operation, which varies according to the attributes (emulation type, capacity size of the data
that is copied, position of the extent) of the volumes, and extents used for establishing the
relationships.
You can use the Compatible FlashCopy Information dialog box (see “Compatible FlashCopy
Information Dialog Box” (page 140) ) to check the number of remaining resources that are currently
available. Check the Compatible FlashCopy Information dialog box when you create a Version 2
relationship.
The following software programs share the resources used for copy operations:
•
ShadowImage for Mainframe
•
XP Business Copy
•
XP Snapshot
•
XP Auto LUN
The resources used by ShadowImage for Mainframe, XP Business Copy, XP Snapshot, and XP Auto
LUN cannot be used for Version 2. The remaining resources are available for Version 2. See the
following manuals for details about calculating the resources used by each software program.
•
Hitachi ShadowImage™ for Mainframe User Guide: HP XP24000 Disk Array,
HP XP20000 Disk Array
•
HP StorageWorks XP24000/XP20000 Business Copy Software User Guide
•
HP StorageWorks XP24000/XP20000 Snapshot User Guide
•
HP StorageWorks XP24000/XP20000 Auto LUN Software User Guide
•
Establishing relationships by volume copying
Use the following expression to calculate the total number of resources to be used per
relationship:
Total number of the differential tables per relationship = ((X) + (Y)) x 15 (Z)
◦ (X): The number of cylinders in the volume.
◦ (Y): The number of control cylinders (see “Number of Control Cylinders for Each Emulation
Type” (page 65) ).
◦ (Z): The number of slots that can be managed by a differential table.
(639 × 32)
Round up the number to the nearest whole number.
“Number of Control Cylinders for Each Emulation Type” (page 65) lists the number of control
cylinders for each emulation type.
Table 39 Number of Control Cylinders for Each Emulation Type
Number of Control Cylinders Emulation Type
7 3380-3
6 3390-3
25 3390-9
23 3390-L
53 3390-M
Calculating the Maximum Number of Version 2 Relationships 65