IBM DS8900F, Introduction And Planning Manual

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– Metro/Global Mirror (a combination of Metro Mirror and Global Mirror)
Metro/Global Mirror is a three-site remote copy solution. It uses synchronous replication to mirror
data between a local site and an intermediate site, and asynchronous replication to mirror data from
an intermediate site to a remote site.
– Multiple Target PPRC
Multiple Target PPRC builds and extends the capabilities of Metro Mirror and Global Mirror. It allows
data to be mirrored from a single primary site to two secondary sites simultaneously. You can define
any of the sites as the primary site and then run Metro Mirror replication from the primary site to
either of the other sites individually or both sites simultaneously.
• Remote mirror and copy for IBM Z environments, which includes z/OS Global Mirror.
Note: When FlashCopy is used on FB (open) volumes, the source and the target volumes must have the
same protection type of either T10 DIF or standard.
The point-in-time and remote mirror and copy features are supported across variousIBM server
environments such as IBM i, System p, and IBM Z , as well as servers from Oracle and Hewlett-Packard.
You can manage these functions through a command-line interface that is called the DS CLI. You can use
the DS8000 Storage Management GUI to set up and manage the following types of data-copy functions
from any point where network access is available:
Point-in-time copy (FlashCopy)
You can use the FlashCopy function to make point-in-time, full volume copies of data, with the copies
immediately available for read or write access. In IBM Z environments, you can also use the FlashCopy
function to perform data set level copies of your data. You can use the copy with standard backup tools
that are available in your environment to create backup copies on tape.
FlashCopy is an optional function.
The FlashCopy function 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 the volume pair
in either case:
• From the time that you initiate a FlashCopy operation until the storage system copies all data from the
source volume to the target volume.
• Until you explicitly delete the FlashCopy relationship if it was created as a persistent FlashCopy
relationship.
One of the main benefits of the FlashCopy function is that the point-in-time copy is immediately available
for creating a backup of production data. The target volume is available for read and write processing so it
can be used for testing or backup purposes. Data is physically copied from the source volume to the
target volume by using a background process. (A FlashCopy operation without a background copy is also
possible, which allows only data modified on the source to be copied to the target volume.) The amount of
time that it takes to complete the background copy depends on the following criteria:
• The amount of data to be copied
• The number of background copy processes that are occurring
• The other activities that are occurring on the storage systems
The FlashCopy function supports the following copy options:
Consistency groups
Creates a consistent point-in-time copy of multiple volumes, with negligible host impact. You can
enable FlashCopy consistency groups from the DS CLI.
44 IBM DS8900F: DS8900F Introduction and Planning Guide