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

Glossary
Business Recovery Service
Glossary 429
Glossary
A
application restart Starting an
application, usually on another node, after a
failure. Application can be restarted
manually, which may be necessary if data
must be restarted before the application can
run (example: Business Recovery Services
work like this.) Applications can by restarted
by an operator using a script, which can
reduce human error. Or applications can be
started on the local or remote site
automatically after detecting the failure of
the primary site.
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 MC/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.
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.
asymmetrical cluster A cluster that has
more nodes at one site than at another. For
example, an asymmetrical metropolitan
cluster may have two nodes in one building,
and three nodes in another building.
Asymmetrical clusters are not supported in
all disaster tolerant architectures.
automatic failover Failover directed by
automation scripts or software (such as
MC/ServiceGuard) and requiring no human
intervention. In a ContinentalClusters
environment, the start-up of package
recovery groups on the Recovery Cluster
without intervention. See also application
restart.
B
bi-directional configuration A
continental cluster configuration in which
each cluster serves the roles of primary and
recovery cluster for different recovery
groups. Also known as a mutual recovery
configuration.
BC (Business Copy) A PVOL or SVOL in an
HP StorageWorks 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 taken at a known point
in time. Although this copy, when split, is
often consistent, it is not usually current.
BCV (Business Continuity Volume) An
EMC Symmetrix term that refers to a logical
device on the EMC Symmetrix that may be
merged into or split from a regular R1 or R2
logical device. It is often used to create a
snapshot of the data taken at a known point
in time. Although this copy, when split, is
often consistent, it is not usually current.
Business Recovery Service Service
provided by a vendor to host the backup
systems needed to run mission critical
applications following a disaster.