6 Resilience and Recovery Free Online FlashCards

What does resilience mean for a system?

Resilience is a system’s ability to continue delivering essential services during disruption and restore normal operation afterward.

How does redundancy improve availability?

Redundancy provides alternate components or paths so that one failure does not stop the whole service.

Why can two redundant servers still fail together?

Components that share dependencies, such as one power supply or network switch, may fail together. Distributing them across suitable failure domains reduces this risk.

Why doesn’t replication replace backups?

Replication can also copy accidental deletion, corruption, or malicious changes. Backups provide recoverable copies for restoring earlier data or system states.

What is a backup?

A backup is a recoverable copy of data or system state kept for restoration after loss or damage.

How can backup copies be protected from compromise?

Protect backups with encryption, restricted access, and separation from ordinary production credentials and systems. Immutable or offline copies can further limit alteration or deletion.

How can you verify that a backup is usable?

Periodically restore backups and verify their completeness, consistency, and usability; record the procedure and results.

What is fault isolation?

Fault isolation confines a failure to a defined boundary so unaffected parts can continue operating. Resource limits, timeouts, health checks, and controlled retries can help contain failures.

What is the purpose of a bulkhead design?

A bulkhead design uses independent sections to limit how far damage spreads, like compartments in a ship.

What does a business impact analysis establish for recovery?

A business impact analysis identifies critical services, their dependencies, the consequences of downtime or data loss, and the order for recovery.

What does the recovery time objective (RTO) measure?

The recovery time objective (RTO) is the maximum acceptable time to restore a service.

What does the recovery point objective (RPO) measure?

The recovery point objective (RPO) is the maximum acceptable amount of data loss, expressed as the time between the latest recoverable data and the disruption.