10-HA vs FT vs DR Flashcards
What is High Availability (HA)?
Ensures a system operates for an agreed level of uptime over a long period of time and focuses on maximizing system availability, not eliminating failures or avoid user disruptions entirely.
What are 3 characteristics of HA?
HA systems experience downtime but are designed to recover quickly. Redundancy - HA can have multiple components, such as an active and standby server, that reduce downtime by quickly replacing failed components. User Disruption - Some small user disruptions are acceptable in HA systems.
What is Fault Tolerance (FT)?
Enables a system to continue operating without any disruptions despite failures or faults in its components.
What are 3 characteristics of FT?
No user Disruption - Systems are designed to function seamlessly through failures, often using active-active configurations. Complexity - Systems are more complex and expensive than HA systems. Life Critical Systems - Crucial for systems where even a small disruption could be catastrophic.
What are the differences between HA and FT?
HA minimizes downtime but can allow minor service disruptions during recovery. FT operates through failures with not service disruptions which is often more expensive and harder to design and implement.
What is Disaster Recovery (DR)?
Involves planning and processes to recover or continue operations after a disaster (natural or human-induced) that disables systems.
What are 3 characteristics of DR?
1.Pre-planning - Involves creating policies, tools, and procedures before a disaster occurs which includes things like off-site backups and cloud environments ready to restore operations. 2.Execution - Processes to ensure business continuity, such as moving to a standby site or restoring systems from backups. 3.Periodic Testing - Regularly testing DR processes ensures preparedness and reduces errors during an actual disaster.
