IBM TotalStorage DS6000 Attachment Manual page 37

volume and target volume. A FlashCopy relationship is a "mapping" of a FlashCopy
source volume and a FlashCopy target volume. This mapping allows a point-in-time
copy of the source volume to be copied to the target volume. The FlashCopy
relationship exists between the volume pair from the time that you initiate a
FlashCopy operation until the DS6000 copies all data from the source volume to the
target volume or until you delete the FlashCopy relationship, if it is a persistent
FlashCopy.
The point-in-time copy that is created by FlashCopy is typically used when you
need a copy of the production data to be produced with minimal application
downtime. It can be used for online back up, testing of new applications, or for
creating a database for data-mining purposes. The copy looks exactly like the
original source volume and is an instantly available, binary copy.
FlashCopy supports the following copy options:
Data Set FlashCopy
Data Set FlashCopy allows a FlashCopy of a data set in a zSeries
environment.
Multiple relationship FlashCopy
Multiple relationship FlashCopy allows a source to have FlashCopy
relationships with multiple targets simultaneously. This flexibility allows you
to establish up to 12 FlashCopy relationships on a given logical unit number
(LUN), volume, or data set, without needing to first wait for or cause
previous relationships to end.
Refresh target volume (also known as incremental FlashCopy)
Refresh target volume provides the ability to "refresh" a LUN or volume
involved in a FlashCopy relationship. When a subsequent FlashCopy
operation is initiated, only data that updates the target and the source to the
same point-in-time state is copied. The direction of the "refresh" can also
be reversed. The LUN or volume that was defined as the target can now
become the source for the LUN or the volume that was defined as the
source (now the target).
Persistent FlashCopy
Persistent FlashCopy allows the FlashCopy relationship to remain even
after the FlashCopy operation completes. You must explicitly delete the
relationship.
Establish FlashCopy on existing Remote Mirror and Copy source
The establish FlashCopy on an existing Remote Mirror and Copy source
volume option allows you to establish a FlashCopy relationship where the
target volume is also the source of an existing remote mirror and copy
source volume. This enables you to create full or incremental point-in-time
copies at a local site and then use remote mirroring commands to copy the
data to the remote site.
This feature is represented by the Establish target on existing Metro
Mirror source selection in the GUI.
Consistency group commands
Consistency group commands allow the DS6000 to freeze I/O activity to a
LUN or volume until you issue the FlashCopy consistency group command.
Consistency groups help create a consistent point-in-time copy across
multiple LUNs or volumes, and even across multiple DS6000 systems. This
function is available through the use of command-line interface commands.
7
Chapter 1. Introduction