Filter
Top Products
116 DS8000 Series: Concepts and Architecture
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.