Availability Glossary

Browse 21 availability terms defined in plain English, from the cultural dictionary of computing.

21 Availability Terms

Availability Pattern
A recurring design approach used to keep systems responsive and recoverable despite failures, such as retries, circuit breakers, failover, replication, and...
Bandwidth Throttling Attack
An attack or abuse pattern aimed at degrading service by exhausting or constraining available bandwidth rather than fully crashing the target outright. It can...
DDoS
Distributed Denial of Service — an attack that floods a target server or network with traffic from many compromised machines simultaneously, overwhelming it...
DHCP Starvation
An attack that exhausts the available IP leases on a DHCP server by flooding it with fake client requests, often using many spoofed MAC addresses. Once the...
Distributed Denial of Service
An attack that overwhelms a target's network, service, or application using traffic or requests generated from many distributed systems at once. The...
Downtime
A period when a system, service, or component is unavailable or not functioning as intended for users. It is one of the most direct signals of operational...
Fail-Closed
Fail-Closed is a design behavior where a system denies access when a control fails rather than allowing unsafe operation. Security teams use it to enforce...
Fail-Open
Fail-Open is a design behavior where a system stays available when a control fails, even if that weakens security. Security teams use it to enforce trust,...
Flood Attack
An attack that overwhelms a service, link, or system by sending a high volume of traffic or requests until resources are exhausted. Flood attacks can target...
High Availability Security
The security and resilience measures used to keep critical services available even during attacks, failures, or maintenance events. It combines redundancy,...
Hot Standby Security
The security considerations around hot-standby systems that remain synchronized and ready to take over immediately if the primary system fails. Because standby...
Jamming
The deliberate interference with wireless communications by transmitting noise or competing signals that disrupt reception. Jamming affects availability rather...
Maintenance Window Security
The security planning and controls applied during approved maintenance windows when systems are intentionally changed, restarted, or exposed to elevated admin...
No Downtime
Describing a deployment, migration, or system change intended to occur without causing visible service interruption for users. In practice it usually means...
Operational Resilience
The ability of an organization to continue delivering critical services during and after disruptions such as cyberattacks, outages, third-party failures, or...
Quota Exhaustion
The consumption of a system's allowed limit for requests, storage, API calls, or another bounded resource so legitimate operations are blocked or degraded....
Redundancy Security
The security and reliability considerations around redundant systems, links, or components designed to keep services running during failures or attacks....
Repository Mirror
A copied or synchronized version of a repository hosted in another location for availability, redundancy, or distribution reasons. In infrastructure and...
Resource Exhaustion
A condition in which CPU, memory, file handles, threads, storage, connection slots, or another limited resource is consumed until normal operations fail....
RTO
Short for recovery time objective, the maximum acceptable time a system or service can remain unavailable after a disruption. RTO is used in continuity...
Six Nines
A shorthand boast or target for extremely high availability, roughly 99.9999 percent uptime. In engineering slang, six nines often carries a skeptical tone...

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