HP Serviceguard Metrocluster manual Span 100s or 1000s of kilometers

	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
	P9000 Disk Array family, HP StorageWorks E Disk Array XP series. This facility enables physical
	data replication between P9000 and 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 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
	might cause the replica to lag behind the primary copy, and compromise data currency.
data loss	The inability to take action to recover data. Data loss can be the result of transactions being
	copied that were lost when a failure occurred, non-committed transactions that were rolled back
	as pat of a recovery process, data in the process of being replicated that never made it to the
	replica because of a failure, transactions that were committed after the last tape backup when a
	failure occurred that required a reload from the last tape backup. transaction processing monitors
	(TPM), message queuing software, and synchronous data replication are measures that can
	protect against data loss.
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.
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	A cluster architecture that protects against multiple points of failure or a single catastrophic failure
architecture	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 recovery 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.
disaster recovery	Services and products offered by companies that provide the hardware, software, processes,
services	and people necessary to recover from a disaster.
E, F
Environment File	Metrocluster uses a configuration file that includes variables that define the environment for the
	Metrocluster to operate in a Serviceguard cluster. This configuration file is referred to as the
	Metrocluster environment file. This file needs to be available on all the nodes in the cluster for
	Metrocluster to function successfully.
event log	The default location (/var/opt/resmon/log/cc/eventlog) where events are logged on
	the monitoring Continentalclusters system. All events are written to this log, as well as all
	notifications that are sent elsewhere.
failback	Failing back from a backup node, which might or might not be remote, to the primary node that
	the application normally runs on.
failover	The transfer of control of an application or service from one node to another node after a failure.
	Failover can be manual, requiring human intervention, or automated, requiring little or no human
	intervention.

146 Glossary