Flashcopy - IBM TotalStorage DS6000 Introduction And Planning Manual

FlashCopy

The FlashCopy function enables you to make point-in-time, full volume copies of
data, with the copies immediately available for read or write access. You can use
the copy with standard backup tools that are available in your environment to create
backup copies on tape.
FlashCopy creates a copy of a source volume on the target volume. This copy is
called a point-in-time copy. When you initiate a FlashCopy operation, a FlashCopy
relationship is created between a source volume and target volume. A FlashCopy
relationship is a "mapping" of the FlashCopy source volume and a FlashCopy
target volume. This mapping allows a point-in-time copy of that source volume to be
copied to the associated target volume. The FlashCopy relationship exists between
this volume pair from the time that you initiate a FlashCopy operation until the
storage unit copies all data from the source volume to the target volume or you
delete the FlashCopy relationship, if it is a persistent FlashCopy.
The benefits of FlashCopy are that the point-in-time copy is immediately available
for use for backups and that the source volume is immediately released so that
applications can be restarted, with minimal application downtime. The target volume
is available for read and write processing so it can be used for testing or backup
purposes.
When the data is physically copied, a background process copies tracks from the
source volume to the target volume. The amount of time that it takes to complete
the background copy depends on the following criteria:
v The amount of data being copied
v The number of background copy processes that are occurring
v The other activities that are occurring on the DS6000 series
FlashCopy supports the following copy options:
Consistency groups
Change recording
Establish FlashCopy on existing Metro Mirror source
Fast reverse
Inhibit writes to target
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Introduction and Planning Guide
Creates a consistent point-in-time copy of multiple volumes, with negligible
host impact. You can enable FlashCopy consistency groups from the
command-line interface (DS CLI).
Activates the change recording function on the volume pair that is
participating in a FlashCopy relationship. This enables a subsequent refresh
to the target volume.
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.
Reverses the FlashCopy relationship without waiting for the finish of the
background copy of the previous FlashCopy. This option applies to the
Global Mirror mode.
Ensures that write operations are inhibited on the target volume until a
refresh FlashCopy operation is complete.