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v Remote data mirroring. HACMP/XD for GLVM creates a remote mirror copy of the data that the
application can access both at the local site and at the remote site.
The software protects critical data by mirroring of the non-concurrent volume groups to which the
application sends I/O requests. The application can access the same data regardless of whether the
application is running on the local or remote site.
The data mirroring function utilizes the mirroring capabilities of the AIX Logical Volume Manager
along with the mirroring function of the Geographic Logical Volume Manager that is provided by the
HACMP/XD for GLVM software.
v Integration with HACMP. By integrating with HACMP, HACMP/XD for GLVM keeps mission-critical
systems and applications operational in the event of disasters. It manages the fallover and fallback of
the resource group that contains the application.
Upon a node, a network interface, or a site failure, HACMP/XD for GLVM moves the resource group
to another node. The node may belong either to the same site or to a remote site. With this operation, a
complete, up-to-date copy of the volume group's data remains available for the application to use on
the node at the same site or at another site.
When the application is moved to a remote site, HACMP/XD for GLVM continues to mirror the data.
Related information:
Geographic LVM Planning and administration
HACMP/XD for Metro Mirror overview
IBM HACMP/XD for Metro Mirror increases data availability for IBM TotalStorage Enterprise Storage
Server
®
(ESS) volumes, DS600 volumes, and DS8000 volumes that use Peer-to-Peer Remote Copy (PPRC)
to copy data to a remote site for disaster recovery purposes. HACMP/XD for Metro Mirror takes
advantage of the PPRC fallover/fallback functions and HACMP cluster management to reduce downtime
and recovery time during disaster recovery.
HACMP/XD Metro Mirror for SVC provides a fully automated, highly available disaster recovery
management solution that takes advantage of the SAN Volume Controller's ability to provide virtual
disks derived from varied disk subsystems. The HACMP interface is designed so that once the basic SVC
environment is configured, PPRC relationships are created automatically; no additional access to the SVC
interface is needed.
Related information:
PPRC Planning and administration
Cross-site LVM overview
Cross-site LVM mirroring replicates data between the disk subsystem at each site for disaster recovery.
You can set up disks located at two different sites for remote mirroring.
A storage area network (SAN) is a high-speed network that allows the establishment of direct connections
between storage devices and processors (servers) within the distance supported by Fibre Channel. Thus,
two or more servers (nodes) located at different sites can access the same physical disks, which can be
separated by some distance as well, through the common SAN.
These remote disks can be combined into a volume group via the AIX Logical Volume Manager and this
volume group can be imported to the nodes located at different sites. The logical volumes in this volume
group can have up to three mirrors. Thus you can set up a mirror at each site. The information stored on
this logical volume is kept highly available, and in case of certain failures, the remote mirror at another
site will still have the latest information, so the operations can be continued on the other site.
HACMP automatically synchronizes mirrors after a disk or node failure and subsequent reintegration.
HACMP handles the automatic mirror synchronization even if one of the disks is in the PVREMOVED or
PVMISSING state. Automatic synchronization is not possible for all cases, but you can use C-SPOC to
synchronize the data from the surviving mirrors to stale mirrors after a disk or site failure and
subsequent reintegration.
Planning 9