Designing Disaster Tolerant High Availability Clusters, 10th Edition, March 2003 (B7660-90013)

Physical Data Replication for ContinentalClusters Using Continuous Access XP
Overview
Chapter 6 287
• Raid Manager XP host-based software for control and status of the
XP series disk arrays.
• MC/ServiceGuard
NOTE Ensure that you have the most recent version for HP-UX,
ContinentalCluster, Raid Manager, and MC/ServiceGuard by referring
to most current ContinentalClusters release notes.
The procedures in this chapter assume that you are configuring one or
more ServiceGuard application packages whose data reside on the XP
disks and are replicated between the two XP disk arrays with
Continuous Access XP. The procedures must be repeated for each
application package.
Continuous Access can be configured in either synchronous or
asynchronous mode. Asynchronous mode is enabled by setting the FENCE
parameter to ASYNC in the package configuration ASCII file.
While the cluster is running, all the XP devices (LUNs) that belong to the
same package and are defined in a single Raid Manager device group
must be in the same state at the same time. Manual changes of these
states can cause the package to halt or to not start up properly due to
unexpected conditions. In general, it is recommended that no manual
changes of state be performed while the package and cluster are running,
except during the repair process. (For example, it is acceptable to run
pairresync to recover from a complete CA link failure. However, if
manual changes are made during the repair process, devices must be
returned to their original states afterwards.)
WARNING The logic of the special XPCA integration scripts always assumes
that a given PVOL/SVOL state combination was not due to
manual configuration changes.