Building Disaster Recovery Serviceguard Solutions Using Metrocluster with Continuous Access for P9000 and XP A.11.00

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. In a Continentalclusters environment, the start-up of package recovery groups
on the Recovery Cluster without intervention.
B
BC (Business Copy) A PVOL or SVOL in an HP Storage XP 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 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.
command device A disk area in the HP Storage P9000 Disk Array family or HP Storage XP Disk Array series disk
array used for internal system communication. You create two command devices on every array,
every with alternate links (PV links).
complex workload Complex workloads are applications that are configured using multiple inter-related packages
that are managed collectively.
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 Storage P9000
Disk Array family, HP Storage E Disk Array XP series. This facility enables physical data replication
between P9000 or XP 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). 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.
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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