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

Glossary
mission critical solution
Glossary 433
H, I
heartbeat network A network that
provides reliable communication among
nodes in a cluster, including the
transmission of heartbeat messages, signals
from each functioning node, which are
central to the operation of the cluster, and
which determine the health of the nodes in
the cluster.
high availability A combination of
technology, processes, and support
partnerships that provide greater
application or system availability.
J, K, L
local cluster A cluster located in a single
data center. This type of cluster is not
disaster tolerant.
local failover Failover on the same node;
this most often applied to hardware failover,
for example local LAN failover is switching
to the secondary LAN card on the same node
after the primary LAN card has failed.
logical data replication A type of on-line
data replication that replicates logical
transactions that change either the
filesystem or the database. Complex
transactions may result in the modification
of many diverse physical blocks on the disk.
LUN (Logical Unit Number) A SCSI term
that refers to a logical disk device composed
of one or more physical disk mechanisms,
typically configured into a RAID level.
M
M by N A type of Symmetrix grouping in
which up to two Symmetrix frames may be
configured on either side of a data
replication link in a MetroCluster/SRDF
configuration. M by N configurations include
1 by 2, 2 by 1, and 2 by 2.
manual failover Failover requiring human
intervention to start an application or
service on another node.
MetroCluster A Hewlett-Packard product
that allows a customer to configure an
MC/ServiceGuard cluster as a disaster
tolerant metropolitan cluster.
metropolitan cluster A cluster that is
geographically dispersed within the confines
of a metropolitan area requiring right-of-way
to lay cable for redundant network and data
replication components.
mirrored data Data that is copied using
mirroring.
mirroring Disk mirroring hardware or
software, such as MirrorDisk/UX. Some
mirroring methods may allow splitting and
merging.
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.