Building Disaster Recovery Serviceguard Solutions Using Metrocluster with Continuous Access XP P9000 for Linux B.12.00.00

Glossary
A
arbitrator Nodes in a disaster tolerant architecture that act as tie-breakers in case all of the nodes in a data
center go down at the same time. These nodes are full members of the Serviceguard cluster and
must conform to the minimum requirements. The arbitrator must be located in a third data center
to ensure that the failure of an entire data center does not bring the entire cluster down.
asynchronous data
replication
Local I/O will complete without waiting for the replicated I/O to complete; however, it is expected
that asynchronous data replication will process the I/Os in the original order.
automatic failover Failover directed by automation scripts or software (such as Serviceguard) and requiring no
human intervention.
B
BC (Business Copy) A PVOL or SVOL in an HP Storage P9000 series disk array that can be split from
or merged into a normal PVOL or SVOL. It is often used to create a snapshot of the data brought
at a known point in time. Although this copy, when split, is often consistent, it is not usually current.
C
cluster A Serviceguard cluster is a networked grouping of nodes having sufficient redundancy of software
and hardware that a single failure will not significantly disrupt service. Serviceguard software
monitors the health of nodes, networks, application services,and makes failover decisions based
on where the application is able to run successfully.
command device A disk area in the HP Storage P9000 Disk Array family used for internal system communication.
Continuous Access A facility provided by the Continuos Access software option available with available with the HP
Storage P9000 Disk Array family. This facility enables physical data replication between P9000
series disk arrays.
D
data center A physically proximate collection of nodes and disks, usually all in one room.
data consistency Whether data are logically correct and immediately usable; the validity of the data after the last
write. Inconsistent data, if not recoverable to a consistent state, is corrupt.
data mirroring See See mirroring..
data replication The scheme by which data is copied from one site to another for disaster tolerance. Data replication
can be either physical (see physical data replication) or logical (see logical data replication).
disaster An event causing the failure of multiple components or entire data centers that render unavailable
all services at a single location; these include natural disasters such as earthquake, fire, or flood,
acts of terrorism or sabotage, large-scale power outages.
disaster recovery The process of restoring access to applications and data after a disaster. Disaster recovery can
be manual, meaning human intervention is required, or it can be automated, requiring little or
no human intervention.
disaster recovery
services
Services and products offered by companies that provide the hardware, software, processes,
and people necessary to recover from a disaster.
disaster tolerant The characteristic of being able to recover quickly from a disaster. Components of disaster
tolerance include redundant hardware, data replication, geographic dispersion, partial or complete
recovery automation, and well-defined recovery procedures.
disaster tolerant
architecture
A cluster architecture that protects against multiple points of failure or a single catastrophic failure
that affects many components by locating parts of the cluster at a remote site and by providing
data replication to the remote site. Other components of disaster tolerant architecture include
redundant links, either for networking or data replication, that are installed along different routes,
and automation of most or all of the recovery process.
71