{{Unreferenced, date=December 2009
Extended Remote Copy or XRC is an IBM
zSeries
IBM Z is a family name used by IBM for all of its z/Architecture mainframe computers.
In July 2017, with another generation of products, the official family was changed to IBM Z from IBM z Systems; the IBM Z family now includes the newest mo ...
and
System z9
IBM System z9 is a line of IBM mainframe computers. The first models were available on September 16, 2005. The System z9 also marks the end of the previously used eServer zSeries naming convention. It was also the last mainframe compute ...
mainframe computer
A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterpris ...
technology for
data replication
Replication in computing involves sharing information so as to ensure consistency between redundant resources, such as software or hardware components, to improve reliability, fault-tolerance, or accessibility.
Terminology
Replication in com ...
. It combines supported hardware and
z/OS
z/OS is a 64-bit operating system for IBM z/Architecture mainframes, introduced by IBM in October 2000. It derives from and is the successor to OS/390, which in turn was preceded by a string of MVS versions.Starting with the earliest:
...
software to provide asynchronous replication over long distances. It is complementary to IBM's Peer to Peer Remote Copy (PPRC) service, which is designed to operate either synchronously or asynchronously over shorter distances.
XRC as a z/OS copy services solution can be compared to
Global Mirror Global Mirror is an IBM technology that provides data replication over extended distances between two sites for business continuity and disaster recovery. If adequate bandwidth exists, Global Mirror provides a recovery point objective (RPO) of ...
for ESS, which is a controller-based solution for either the open systems or z/Series environments. Both Global Mirror for ESS (Asynchronous PPRC) and XRC (Global Mirror for z/Series) are asynchronous replication technologies, although their implementations are somewhat different.
Extended Remote Copy or XRC is now known as Global Mirror for z/Series (XRC).
XRC is a z/Series asynchronous disk mirroring technique which is effective over any distance. It keeps the data time consistent across multiple ESS (Enterprise Storage Server) or HDS (Hitachi Data Systems) disk subsystems at the recovery site.
XRC functions as a combination of disk (IBM ESS or HDS licensed) Microcode and application code running on a z/Series host and provides a recovery point that is time consistent across multiple disk subsystems.
The host component of the software is called the System Data Mover or SDM. The SDM ensures that no dependent writes are made out of sequence and data residing on the secondary volumes will always provide a time consistent copy of the primary volumes being mirrored.