Pair volume requirements and recommendations
The following is provided to help you prepare TrueCopy volumes:
• A volume can be assigned to only one pair.
• Logical units on the primary and secondary storage systems must be
defined and formatted prior to pairing.
• The P-VOL and S-VOL must be equal in size.
• TrueCopy requires a one-to-one relationship between the P-VOL and S-
VOL. The P-VOL cannot be copied to more than one S-VOL, and an S-VOL
cannot have more than one P-VOL.
• Logical Unit(LU) Types
¢
TrueCopy supports OPEN V.
¢
Pair volumes must consist of LUs of the same type and capacity. The
P-VOL and S-VOL LU types display in Device Manager - Storage
Navigator.
• TrueCopy operates on volumes rather than on files; multi-volume files
require special attention. For complete duplication and recovery of a
multi-volume file (for example, a large database file that spans several
volumes), make sure that all volumes of the file are copied to TrueCopy
S-VOL.
• TrueCopy pair volumes can be shared with non-TrueCopy Hitachi software
products. See
Chapter 4, Sharing TrueCopy volumes on page 4-1 for
more information.
• TrueCopy supports Virtual LVI/LUN. This allows you to configure LUs that
are smaller than standard LUs. When custom-size LUs are assigned to a
TrueCopy pair, the S-VOL must have the same capacity as the P-VOL.
Device Manager - Storage Navigator displays the size of P-VOLs and S-
VOL.
• Before creating multiple pairs during the Create Pairs operation, make
sure to set up S-VOL LDEVs to allow the system to correctly match them
to P-VOLs.
You must do this because, even though you select multiple volumes as P-
VOLs, you specify just one S-VOL. The system automatically assigns
subsequent secondary system LDEVs as S-VOLs based on the option you
specify for Selection Type. These are the options:
¢
Interval: The interval you specify will be skipped between LDEV
numbers in the secondary system.
For example, suppose you specify LU 01 as the initial (base) S-VOL,
and specify 3 for Interval. This results in secondary system LDEV 04
being assigned to the next P-VOL, 07 assigned to the subsequent P-
VOL, and so on. To use Interval, you set up secondary system LDEV
numbers according to the interval between them.
¢
Relative Primary Volume. The difference is calculated between the
LDEV numbers of two successive P-VOLs. S-VOLs are assigned
according to the closest LUN number.
Planning for TrueCopy
3-9
Hitachi TrueCopy® User Guide for Hitachi Virtual Storage Platform Gx00 and Fx00 Models
To Next Page
Loading...
