Glossary
Monitoring terms, briefly
- Uptime
- The share of time a service was reachable, usually as a percentage over a month. Learn more
- SLA
- Service level agreement: a promised uptime figure with consequences for missing it. Learn more
- Incident
- A period during which a monitor was confirmed down, from first confirmed failure to confirmed recovery. Learn more
- Confirmation
- Re-checking a failure from additional regions before treating it as real. Tenium requires a quorum of regions: 2 of 2 today. Learn more
- Heartbeat
- A monitor that expects an inbound ping on a schedule; used for cron jobs and workers. Learn more
- Keyword check
- An HTTP check that also requires text to be present or absent in the response body. Learn more
- TTFB
- Time to first byte: how long until the server sends the first byte of the response. Learn more
- p95
- The value below which 95% of samples fall; used for response-time alerts to ignore outliers. Learn more
- Status page
- A public page showing the current state and history of monitored components. Learn more
- White-label
- Removing the vendor’s branding so a status page or report appears to come from you. Learn more
- Escalation
- Notifying additional people when an incident is not acknowledged within a set time. Learn more
- Maintenance window
- A scheduled period during which alerts are suppressed and downtime is not counted. Learn more
- RDAP
- Registration Data Access Protocol: the structured successor to WHOIS used for domain expiry lookups. Learn more
- WAF
- Web application firewall, such as Cloudflare’s, which may challenge or block automated checks. Learn more
- MTTR
- Mean time to recover: the average time from the start of an incident to recovery. Lower is better. Learn more
- MTBF
- Mean time between failures: the average time a service runs between incidents. Higher is better. Learn more
- False alert
- An alert for an outage that was not real, for example one failed request from a single bad route. Confirmation before alerting exists to prevent it. Learn more
- Flapping
- A monitor that keeps switching between up and down. It is a paging problem more than a monitoring problem, and escalation delays or confirmation settings tame it. Learn more