M5.5 module quiz
Ten questions. 80% to pass (8 of 10). Open book, unlimited retakes.
Answers are collapsed under each question. Answer first, then check.
Q1
The breakeven calculation for a reliability investment compares:
A. The cost against the provider’s published SLA credit
B. The cost against what comparable peers are spending
C. The annual cost of the investment against the expected annual cost of the downtime it prevents
D. The uptime percentage actually achieved measured against the stated contractual target
Show answer
Correct: C. Both sides need a number. An investment justified by an unquantified fear cannot be compared against anything, including the next one.
Q2
Backup snapshot cost grows with:
A. The volume of retained deltas
B. Retention days multiplied by volume size
C. Restore frequency
D. Region count
Show answer
Correct: A. Snapshots are incremental on all three clouds: the first is roughly full, each subsequent one stores changed blocks. The full-copy model overstates cost by roughly an order of magnitude.
Q3
GFS retention keeps long retention sub-linear because:
A. Old snapshots compress better than recent ones
B. Cloud providers discount storage rates for older backup data automatically
C. Keeping 30 daily, 8 weekly and 12 monthly is far fewer copies than 365 dailies
D. Deltas shrink over time as the data settles down
Show answer
Correct: C. Combined with archive tiers, this is why a seven-year retention is a few TB of overlapping deltas rather than 2,555 full copies.
Q4
Retention should be set by:
A. The cloud provider’s own default retention policy
B. RTO, RPO and compliance requirements, and nothing more
C. The largest team’s stated preference
D. Whatever the available budget allows
Show answer
Correct: B. Anything beyond those three is cost with no stated benefit, and “just in case” is the phrase that produces indefinite retention.
Q5
DR cost scales primarily with:
A. The total volume of data being replicated
B. The number of regions in scope
C. Which provider is being used
D. How aggressive the RTO and RPO targets are
Show answer
Correct: D. Backup-and-restore, pilot light, warm standby and active-active form a cost ladder, and each step buys a shorter RTO.
Q6
An untested DR plan is:
A. A reliability investment whose benefit is unverified
B. Better than having nothing at all in place today
C. Sufficient to satisfy a compliance auditor
D. Equivalent to a tested one in practice
Show answer
Correct: A. It is one of the five reliability-theatre patterns: the spend is real and the protection is assumed rather than demonstrated.
Q7
“Multi-AZ that doesn’t help” describes:
A. Multi-AZ deployed on an entirely non-critical workload
B. Multi-AZ contained within a single region
C. Multi-AZ deployed without any backups
D. Multi-AZ where a single-AZ dependency remains in the path
Show answer
Correct: D. The redundant component cannot compensate for the one that is not, so the spend buys availability the architecture cannot deliver.
Q8
Tiered reliability means:
A. All workloads receive exactly the same reliability treatment
B. Reliability decided by the provider’s defaults
C. Reliability investment matched to each workload’s business impact
D. Reliability decided independently by each team
Show answer
Correct: C. Without tiers, the org either over-protects everything or protects the loudest team’s workload, and neither matches impact.
Q9
Excessive health checks and alerts count as reliability theatre because:
A. They cost real money to keep running
B. They produce noise that degrades the response to real incidents
C. They slow down the deployment pipeline
D. They require ongoing maintenance effort to keep them working
Show answer
Correct: B. The cost is the alert fatigue rather than the compute, and the failure surfaces during the incident that gets missed among the false ones.
Q10
The right response to discovering reliability theatre is:
A. Either make the protection real or consciously accept the simpler design
B. Remove the redundant reliability spend immediately and then move on
C. Add more redundancy to close the gap
D. Escalate the decision to leadership
Show answer
Correct: A. Removing the spend without deciding which of the two you are choosing leaves the same exposure with a smaller bill and no decision behind it.
What’s next
Back to Reliability vs cost.