HP Serviceguard Metrocluster manual Glossary, See also quorum server

Glossary

A
application restart	Starting an application, usually on another node, after a failure. Application can be restarted
	manually, which might 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 recovery 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.
B
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
	brought 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 might be merged into or split from a regular R1 or R2 logical device. 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.
Business Recovery	Service provided by a vendor to host the backup systems required to run mission critical
Service	applications following a disaster.
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	A cluster in production that has packages protected by the HP Continentalclusters product.
cluster alarm	Time at which a message is sent indicating that the cluster is probably in need of recovery. The
	cmrecoverclcommand is enabled at this time.
cluster alert	Time at which a message is sent indicating a problem with the cluster.
cluster event	A cluster condition that occurs when the cluster goes down or enters an UNKNOWN state, or
	when the monitor software returns an error. This event might cause an alert messages to be sent
	out, or it might cause an alarm condition to be set, which allows the administrator on the Recovery
	Cluster to issue the cmrecovercl command. The return of the cluster to the UP state results in
	a cancellation of the event, which might be accompanied by a cancel event notice. In addition,
	the cancellation disables the use of the cmrecovercl command.
cluster quorum	A dynamically calculated majority used to determine whether any grouping of nodes is sufficient
	to start or run the cluster. Cluster quorums prevent split-brain syndrome which can lead to data
	corruption or inconsistency. Currently at least 50% of the nodes plus a tie-breaker are required
	for a quorum. If no tie-breaker is configured, then greater than 50% of the nodes is required to
	start and run a cluster.
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

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