Lesson 11: High Availability and Disaster Recovery
Week of Tue, Nov 24 · lesson closes Mon, Nov 30
Take Meerk's quiz for Lesson 11
This lesson's items
Exact due times are in Canvas.
Watch — Professor Messer
Watch — Professor Messer: High Availability (N10-009)
Free, independent educational resource. Not affiliated with or endorsed by CompTIA. Watch, then read the notes below.
Know these cold
- HA metrics: MTTR (Mean Time to Repair — how long to fix), MTBF (Mean Time Between Failures — how long it lasts), availability % = MTBF / (MTBF + MTTR).
- HSRP/VRRP: First Hop Redundancy Protocols (FHRP). Two routers share a virtual IP — one active, one standby. Failover is transparent to clients.
- Load balancing: distributes traffic across multiple servers. Algorithms: round-robin, least connections, weighted. Layer 4 (IP/port) vs. Layer 7 (URL/cookie).
Meerk's quiz — open the Lesson 11 gate
10 questions, no time limit. 85% on your first attempt in a 24-hour window opens the gate. Retakes inside the window are practice — they help you learn, they don't count. Work alone; the point is to know it, not to have seen it.
Dinner Table Question
Ask at home: What is the difference between high availability and a backup — aren't they the same thing?
En español: ¿Cuál es la diferencia entre alta disponibilidad y una copia de seguridad — ¿no son lo mismo?