HP XP P9500 Storage - Manual (Page 5)

1 Overview of Compatible XRC
Unless otherwise specified, the term P9000 in this guide refers to the following disk array:
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P9500 Disk Array
The GUI illustrations in this guide were created using a Windows computer with the Internet Explorer
browser. Actual windows may differ depending on the operating system and browser used. GUI
contents also vary with licensed program products, storage system models, and firmware versions.
This chapter provides an overview of the Compatible XRC feature and configuration.
Function overview
The Compatible XRC feature for the P9500 storage systems provides compatibility with IBM z/OS
Global Mirror (previously called Extended Remote Copy (XRC)) asynchronous remote copy
operations for data backup and recovery in the event of a disaster.
Compatible XRC, used in mainframe systems, has interoperability with IBM Extended Remote Copy
(hereinafter called "XRC") feature and is provided as the program product. Compatible XRC is
compatible with System Data Mover (SDM) in Data Facility Storage Management Subsystem
(DFSMS), which is common to the XRC environment. Compatible XRC operations are performed
in a similar way of XRC by issuing Time Sharing Option (TSO) commands from the host system to
the logical devices on the P9500 storage system.
In Compatible XRC operations, the data written from the primary host at the primary site is written
to the primary volume by means of the cache memory at the primary P9500 storage system. At
the same time, the data is temporarily stored in cache memory as a sidefile. At the secondary site,
the System Data Mover (SDM) software asynchronously reads the sidefile data over communication
lines from the primary storage system at the primary site. SDM then writes the data to the secondary
volume in the secondary storage system in the same order as it was written at the primary site.
SDM manages pair definitions of the primary and secondary storage systems or pair definitions
of the primary and secondary volumes.
The following shows an overview of Compatible XRC operations.
Figure 1 Overview of Compatible XRC operations
Sessions
In Compatible XRC operations, a group of primary volumes is processed as one session. Data is
written to the secondary volumes in each session in the same order as it was written at the primary
site. In the event of a failure, all volume pairs in the same session are suspended. The write operation
Function overview 5