IBM DS8700, Introduction And Planning Manual

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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
various IBM server environments such as IBM i, System p
®
, and System z, as well
as servers from Sun and Hewlett-Packard.
You can manage these functions through a command-line interface called the DS
CLI and a Web-based interface called the DS Storage Manager. The DS Storage
Manager allows you 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)
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. In System 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. To use it, you must purchase one of the
point-in-time 242x indicator feature and 239x function authorization features.
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 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.
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
using a background process. (A FlashCopy operation without a background copy is
also possible, which allows only data that is 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:
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 storage units
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.
Chapter 3. Data management features
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