7.1 Introduction to Copy Services

Copy Services is a collection of functions that provide disaster recovery, data migration, and data duplication functions. With the Copy Services functions, for example, you can create backup data with little or no disruption to your application, and you can back up your application data to the remote site for the disaster recovery.

Copy Services run on the DS8000 storage unit and support open systems and zSeries environments. These functions are supported also on the previous generation of storage systems called the IBM TotalStorage Enterprise Storage Server (ESS).

Many design characteristics of the DS8000 and data copying and mirroring capabilities of Copy Services features contribute to the protection of your data, 24 hours a day and seven days a week. The licensed features included in Copy Services are the following:

￿FlashCopy, which is a Point-in-Time Copy function

￿Remote Mirror and Copy functions, previously known as Peer-to-Peer Remote Copy or PPRC, which include:

IBM TotalStorage Metro Mirror, previously known as Synchronous PPRC

IBM TotalStorage Global Copy, previously known as PPRC Extended Distance

IBM TotalStorage Global Mirror, previously known as Asynchronous PPRC

￿z/OS Global Mirror, previously known as Extended Remote Copy (XRC)

￿z/OS Metro/Global Mirror

We explain these functions in detail in the next section.

You can manage the Copy Services functions through a command-line interface (DS CLI) and a new Web-based interface (DS Storage Manager). You also can manage the Copy Services functions through the open application programming interface (DS Open API). When you manage the Copy Services through these interfaces, these interfaces invoke Copy Services functions via the Ethernet network. In zSeries environments, you can invoke the Copy Service functions by TSO commands, ICKDSF, the DFSMSdss™ utility, and so on.

We explain these interfaces in 7.3, “Interfaces for Copy Services” on page 136.

7.2 Copy Services functions

We describe each function and the architecture of the Copy Services in this section. There are two primary types of Copy Services functions: Point-in-Time Copy and Remote Mirror and Copy. Generally, the Point-in-Time Copy function is used for data duplication and the Remote Mirror and Copy function is used for data migration and disaster recovery.

7.2.1 Point-in-Time Copy (FlashCopy)

The Point-in-Time Copy feature, which includes FlashCopy, enables you to create full volume copies of data in a storage unit. When you set up a FlashCopy operation, a relationship is established between the source and target volumes, and a bitmap of the source volume is created. Once this relationship and bitmap are created, the target volume can be accessed as though all the data had been physically copied. While a relationship between the source and target volume exists, optionally, a background process copies the tracks from the source to the target volume.

116DS8000 Series: Concepts and Architecture

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IBM DS8000 manual Introduction to Copy Services, Copy Services functions, Point-in-Time Copy FlashCopy