IBM DS8880 Series, Introduction And Planning Manual

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The z/OS Metro/Global Mirror Incremental Resync capability is intended
to enhance this solution by enabling resynchronization of data between
sites by using only the changed data from the Metro Mirror target to the
z/OS Global Mirror target after a HyperSwap operation.
If an unplanned failover occurs, you can use the z/OS Soft Fence function
to prevent any system from accessing data from an old primary PPRC site.
For more information, see the GDPS/PPRC Installation and Customization
Guide, or the GDPS/PPRC HyperSwap Manager Installation and Customization
Guide.
z/OS Global Mirror Multiple Reader (enhanced readers)
z/OS Global Mirror Multiple Reader provides multiple Storage Device
Manager readers that allow improved throughput for remote mirroring
configurations in IBM Z environments. z/OS Global Mirror Multiple
Reader helps maintain constant data consistency between mirrored sites
and promotes efficient recovery. This function is supported on the storage
system running in a IBM Z environment with version 1.7 or later at no
additional charge.
Interoperability with existing and previous generations of the
DS8000 series
All of the remote mirroring solutions that are documented in the sections above
use Fibre Channel as the communications link between the primary and secondary
storage systems. The Fibre Channel ports that are used for remote mirror and copy
can be configured as either a dedicated remote mirror link or as a shared port
between remote mirroring and Fibre Channel Protocol (FCP) data traffic.
The remote mirror and copy solutions are optional capabilities and are compatible
with previous generations of DS8000 series. They are available as follows:
v Metro Mirror indicator feature numbers 75xx and 0744 and corresponding
DS8000 series function authorization (2396-LFA MM feature numbers 75xx)
v Global Mirror indicator feature numbers 75xx and 0746 and corresponding
DS8000 series function authorization (2396-LFA GM feature numbers 75xx).
Global Copy is a non-synchronous long-distance copy option for data migration
and backup.
Disaster recovery through Copy Services
Through Copy Services functions, you can prepare for a disaster by backing up,
copying, and mirroring your data at local and remote sites.
Having a disaster recovery plan can ensure that critical data is recoverable at the
time of a disaster. Because most disasters are unplanned, your disaster recovery
plan must provide a way to recover your applications quickly, and more
importantly, to access your data. Consistent data to the same point-in-time across
all storage units is vital before you can recover your data at a backup (normally
your remote) site.
Most users use a combination of remote mirror and copy and point-in-time copy
(FlashCopy) features to form a comprehensive enterprise solution for disaster
recovery. In an event of a planned event or unplanned disaster, you can use
failover and failback modes as part of your recovery solution. Failover and failback
modes can reduce the synchronization time of remote mirror and copy volumes
after you switch between local (or production) and intermediate (or remote) sites
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DS8880 Introduction and Planning Guide