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

Glossary
disaster protection
Glossary432
disaster protection (Don’t use this term?)
Processes, tools, hardware, and software
that provide protection in the event of an
extreme occurrence that causes application
downtime such that the application can be
restarted at a different location within a
fixed period of time.
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 services Services and
products offered by companies that provide
the hardware, software, processes, and
people necessary to recover from a disaster.
disaster tolerant The characteristic of
being able to recover quickly from a disaster.
Components of disaster tolerance include
redundant hardware, data replication,
geographic dispersion, partial or complete
recovery automation, and well-defined
recovery procedures.
disaster tolerant architecture A cluster
architecture that protects against multiple
points of failure or a single catastrophic
failure 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
tolerant 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.
E, F
ESCON Enterprise Storage Connect. A
type of fiber-optic channel used for
inter-frame communication between EMC
Symmetrix frames using EMC SRDF or
between HP StorageWorks E XP series disk
array units using Continuous Access XP.
event log The default location
(/var/adm/cmconcl/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.
extended distance cluster A cluster with
alternate nodes located in different data
centers separated by some distance.
Formerly known as campus cluster.
failback Failing back from a backup node,
which may or may 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.
filesystem replication The process of
replicating filesystem changes from one node
to another.
G
gatekeeper A small EMC Symmetrix
device configured to function as a lock
during certain state change operations.