Midterm Flashcards
Providing multiple identical instances of the same system and switching to one of the remaining instances in case of a failure (failover)
Redundancy
is a customizable information store that functions as a single point from which users can locate resources and services distributed throughout the network.
Directory Service
is a server which provides such a service.
Directory Server or Name Server
is an open standard protocol
LDAP
DNS example of directory service
Domain Name System
refers to the ability of a system (computer, network, cloud cluster, etc.) to continue operating without interruption when one or more of its components fail.
Fault Tolerance
is the provision of functional capabilities that would be unnecessary in a fault-free environment. This can consist of backup components that automatically “kick in” if one component fails.
Redundancy
provides additional components, functions, or data items that are unnecessary for fault-free operation.
Space redundancy
the computation or data transmission is repeated and the result is compared to a stored copy of the previous result.
Time redundancy
Providing multiple identical instances of the same system or subsystem, directing tasks or requests to all of them in parallel, and choosing the correct result on the basis of a quorum
Replication
Providing multiple different implementations of the same specification, and using them like replicated systems to cope with errors in a specific implementation.
Diversity
Backup Components
Hardware systems, Software systems and power sources
that are backed up by identical or equivalent systems.
Hardware systems
that are made fault tolerant using alternative sources.
Power sources
refers to a system’s ability to avoid loss of service by minimizing downtime.
High availability
