Understanding and Designing Serviceguard Disaster Tolerant Architectures Fourth Edition, December 2007 (T1906-90023)

Glossary
mission critical application
Glossary100
mission critical application Hardware,
software, processes and support services
that must meet the uptime requirements of
an organization. Examples of mission critical
application that must be able to survive
regional disasters include financial trading
services, e-business operations, 911 phone
service, and patient record databases.
mission critical solution The architecture
and processes that provide the required
uptime for mission critical applications.
multiple points of failure (MPOF) More
than one point of failure that can bring down
an Serviceguard cluster.
multiple system high availability
Cluster technology and architecture that
increases the level of availability by
grouping systems into a cooperative failover
design.
mutual recovery 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 bi-directional
configuration.
N
network failover The ability to restore a
network connection after a failure in
network hardware when there are
redundant network links to the same IP
subnet.
notification A message that is sent
following a cluster or package event.
O
off-line data replication. Data replication
by storing data off-line, usually a backup
tape or disk stored in a safe location; this
method is best for applications that can
accept a 24-hour recovery time.
on-line data replication Data replication
by copying to another location that is
immediately accessible. On-line data
replication is usually done by transmitting
data over a link in real time or with a slight
delay to a remote site; this method is best for
applications requiring quick recovery
(within a few hours or minutes).
P
package alert Time at which a message is
sent indicating a problem with a package.
package event A package condition such as
a failure that causes a notification message
to be sent. Package events can be
accompanied by alerts, but not alarms.
Messages are for information only; the
cmrecovercl command is not enabled for a
package event.
package recovery group A set of one or
more packages with a mapping between
their instances on the Primary Cluster and
their instances on the Recovery Cluster.
physical data replication An on-line data
replication method that duplicates I/O
writes to another disk on a physical block
basis. Physical replication can be
hardware-based where data is replicated
between disks over a dedicated link (for