196 IBM System Storage Solutions for Smarter Systems
Figure 10-6 shows a basic example of four-node PowerHA cluster that is attached to two
DS8000 storage systems, using Metro Mirror for data replication between remote sites. For
data access, nodes are attached to the local storage system only, although for high availability
reasons, a SAN connection between nodes and storages can be also established, cross-site.
Figure 10-6 IBM PowerHA System Mirror for AIX Enterprise Edition using DS8000 Metro Mirror for
PowerHA System Mirror V6.1 for AIX Enterprise Edition provides integrated support of Metro
Mirror data replication for the Enterprise Storage Server, the DS6000, DS8000, and SAN
Volume Controller, in addition to supporting Global Mirror for DS8700 (R5.1 or later) and the
SAN Volume Controller.
For additional details, see the information available at this website:
10.2.5 Open HyperSwap for AIX with TPC-R
The IBM Tivoli Storage Productivity Center (TPC) for Replication helps to manage the
advanced copy services provided by the DS8000, and the SAN Volume Controller.
Starting with V4.2, the IBM Tivoli Storage Productivity Center for Replication (TPC-R V4.2)
introduced a new feature called Open HyperSwap. Open HyperSwap (comparable to
HyperSwap for System z) helps to improve the continuous availability attributes of open
system servers, such as IBM AIX, by managing a set of planned and unplanned disk system
outages for Metro Mirror PPRC capable disk systems. This is illustrated in Figure 10-7.
This provides a business continuity solution that protects customers from storage failures,
with minimal application impact. Open HyperSwap allows I/O to the primary volumes in a
Metro Mirror relationship to be swapped to the secondary volumes without manual
intervention. After the swap has occurred, the application is automatically writing to the
secondary site without noticing the switch.
Metro Mirror links
Site A Site B
Chapter 10. Continuous operations 197
Figure 10-7 Operation scheme of Open Hyperswap
Open HyperSwap replication is a special replication method, based on Metro Mirror which is
designed to automatically failover I/O from the primary logical devices to the secondary
logical devices in the event of a primary disk storage system failure. Failover is intended to
cause minimal disruption to the application. Open HyperSwap replication applies to both
planned and unplanned replication swaps.
When a session has Open HyperSwap enabled, an I/O error on the primary site automatically
causes the I/O to switch to the secondary site without any user interaction and only minimal
application impact. In addition, when Open HyperSwap is enabled, the Metro Mirror session
also supports disaster recovery. If a write is successful on the primary site but is unable to get
replicated on the secondary site, IBM Tivoli Storage Productivity Center for Replication
suspends all replication for the session, thus ensuring that a consistent copy of the data exists
on the secondary site. If the system fails, this data might not be the latest data, but the data
will be consistent and allow the user to manually switch host servers to the secondary site.
You can control Open HyperSwap from any system running IBM Tivoli Storage Productivity
Center for Replication, on the AIX, Windows, Linux, or z/OS operating systems. However, the
volumes of the Open HyperSwap session must be attached to an AIX host, and an IP
connection between the AIX host system and the Tivoli Storage Productivity Center for
Replication server must be available.
For more information, see these references:
The Redbooks publication,
IBM Tivoli Storage Productivity Center V4.2 -Release Guide,
available at this website:
The IBM Tivoli Storage Productivity Center Information Center’s, Managing a session with
HyperSwap and Open HyperSwap replication, available at this website: