Building Disaster Recovery Serviceguard Solutions Using Metrocluster with Continuous Access EVA P6000 for Linux B.12.00.00

Glossary
A, B
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. See also
quorum server.
automatic failover Failover directed by automation scripts or software (such as Serviceguard) and requiring no
human intervention.
C
campus cluster A single cluster that is geographically dispersed within the confines of an area owned or leased
by the organization such that it has the right to run cables above or below ground between
buildings in the campus. Campus clusters are usually spread out in different rooms in a single
building, or in different adjacent or nearby buildings. See also extended distance cluster.
cluster An Serviceguard cluster is a networked grouping of HP 9000 and/or HP Integrity Servers series
800 servers (host systems known as 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, EMS resources, and makes failover decisions based on
where the application is able to run successfully.
Continentalclusters
A group of clusters that use routed networks and/or common carrier networks for data replication
and cluster communication to support package failover between separate clusters in different
data centers. Continentalclusters are often located in different cities or different countries and can
span 100s or 1000s of kilometers.
Continuous Access A facility provided by the Continuos Access software option available with the HP StorageWorks
P6000/EVA disk Array. This facility enables physical data replication between P6000/EVA
series disk arrays.
Controller
Software
Controller software manages all aspects of array operations, including communication with HP
P6000 Command View. VCS is the controller software for the EVA3000/5000 models. XCS is
the controller software for all other P6000/EVA models.
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 currency Whether the data contain the most recent transactions, and/or whether the replica database has
all of the committed transactions that the primary database contains; speed of data replication
may cause the replica to lag behind the primary copy, and compromise data currency.
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). In
a Continentalclusters environment, the process by which data that is used by the cluster packages
is transferred to the Recovery Cluster and made available for use on the Recovery Cluster in the
event of a recovery.
database
replication
A software-based logical data replication scheme that is offered by most database vendors.
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.
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