IBM DS8700, Введение и руководство по планированию

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data if one host or application fails. This provides increased flexibility to
control the scope of a failover operation and to assign different options and
attributes to each session.
The DS CLI and DS Storage Manager have been enhanced to display
information about the sessions, including the copy state of the sessions.
Metro/Global Mirror
Provides a three-site, long distance disaster recovery replication that
combines Metro Mirror with Global Mirror replication for both System 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, should an outage occur, a backup site
is maintained regardless of which one of the sites is lost. Suppose 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 unit 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, should the intermediate site be 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 reduces the
amount of data that needs to be copied from the local site to the remote
site and the time it takes to do the copy.
z/OS Global Mirror
In the event of 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 related to unexpected
data mover system events.
The z/OS Global Mirror function is an optional function. To use it, you
must purchase the remote mirror for z/OS 242x indicator feature and 239x
function authorization feature.
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
®
situation in
3-site z/OS Metro/Global Mirror configurations. The DS8000 series
supports z/OS Metro/Global Mirror which is a 3-site mirroring solution
that utilizes IBM System Storage Metro Mirror and z/OS Global Mirror
(XRC). The z/OS Metro/Global Mirror Incremental Resync capability is
intended to enhance this solution by enabling resynchronization of data
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Introduction and Planning Guide