Providing Open Architecture High Availability Solutions

Providing Open Architecture High Availability Solutions
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12.0 Glossary
5-nines – Maintaining availability 99.999% of the time.
2-N – A method of redundancy where there is one component in standby for every component in
operation.
Active – Component currently in use providing a service.
Active Fault – A fault that is currently causing an error. Active faults are not necessarily detected,
although they should be in a well-designed HA system.
Active/passive – A system where one redundant component is Active while the other is available,
but not in standby mode.
Active/standby – A system where one redundant component is Active and the other is in standby,
ready to take over with little switchover time or data loss.
Administrative Notification – Notification that is sent though other than the management control
system. This includes notifications with alarms, lights, separate display panels, etc.
Application software – Software which runs above the OS and either above or next to
management middleware. This software typically performs the main functions of the computing
unit, or provides direct support for these functions.
Atomic component – A component that, for the purpose of system description, is not decomposed
into other components.
Attributes – In object-oriented system design, attributes are the characteristics (or parameters) of
an object. See also Methods.
Autonomous Notification – Notification of an error by a unit for an error within that unit. For
example, an OS stack overflow which is detected by the OS.
Checkpoint – The process of copying data from a unit to memory or to the unit’s standby to allow
for switchover while maintaining state.
CM – See Configuration Management.
CMIP – Common Management Information Protocol.
CMIS – Common Management Information Services.
Cold Restart – Restarting a device from power off or with no state information.
Commercial Off The Shelf (COTS) – Products which can readily be purchased by anyone.
Confidentiality – The attribute of not passing information to a unit which does not have rights to
it.
Configuration Management – Controlling the configuration of a system by setting which
components are active, standby or spare and by monitoring the status of components to determine
if they are available, running or failed. Additional configuration management features can provide
more granularity on the control and status of components.