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finish. Global Mirror then starts forming consistency groups again. The
entire pause and resume operation generally takes just a few seconds.
Metro/Global Mirror
Provides a three-site, long-distance disaster recovery replication that
combines Metro Mirror with Global Mirror replication for both IBM Z and
open systems data. Metro/Global Mirror uses synchronous replication to
mirror data between a local site and an intermediate site, and
asynchronous replication to mirror data from an intermediate site to a
remote site.
In a three-site Metro/Global Mirror, if an outage occurs, a backup site is
maintained regardless of which one of the sites is lost. Suppose that an
outage occurs at the local site, Global Mirror continues to mirror updates
between the intermediate and remote sites, maintaining the recovery
capability at the remote site. If an outage occurs at the intermediate site,
data at the local storage system is not affected. If an outage occurs at the
remote site, data at the local and intermediate sites is not affected.
Applications continue to run normally in either case.
With the incremental resynchronization function enabled on a
Metro/Global Mirror configuration, if the intermediate site is lost, the local
and remote sites can be connected, and only a subset of changed data is
copied between the volumes at the two sites. This process reduces the
amount of data needing to be copied from the local site to the remote site
and the time it takes to do the copy.
Multiple Target PPRC
Provides an enhancement to disaster recovery solutions by allowing data
to be mirrored from a single primary site to two secondary sites
simultaneously. The function builds on and extends Metro Mirror and
Global Mirror capabilities. Various interfaces and operating systems
support the function. Disaster recovery scenarios depend on support from
controlling software such as Geographically Dispersed Parallel Sysplex
(GDPS) and IBM Copy Services Manager.
z/OS Global Mirror
If workload peaks, which might temporarily overload the bandwidth of the
Global Mirror configuration, the enhanced z/OS Global Mirror function
initiates a Global Mirror suspension that preserves primary site application
performance. If you are installing new high-performance z/OS Global
Mirror primary storage subsystems, this function provides improved
capacity and application performance during heavy write activity. This
enhancement can also allow Global Mirror to be configured to tolerate
longer periods of communication loss with the primary storage
subsystems. This enables the Global Mirror to stay active despite transient
channel path recovery events. In addition, this enhancement can provide
fail-safe protection against application system impact that is related to
unexpected data mover system events.
The z/OS Global Mirror function is an optional function.
z/OS Metro/Global Mirror Incremental Resync
z/OS Metro/Global Mirror Incremental Resync is an enhancement for
z/OS Metro/Global Mirror. z/OS Metro/Global Mirror Incremental Resync
can eliminate the need for a full copy after a HyperSwap
3-site z/OS Metro/Global Mirror configurations. The storage system
supports z/OS Metro/Global Mirror that is a 3-site mirroring solution that
uses IBM System Storage Metro Mirror and z/OS Global Mirror (XRC).
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Chapter 3. Data management features
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