Object storage tiers and lifecycle automation

WHAT THIS TESTS The interviewer wants to see that you optimize storage cost against access patterns rather than dumping everything in one tier.

A GOOD ANSWER COVERS Explain the fundamental trade-off: cheaper tiers cost less per gigabyte stored but more per gigabyte retrieved, and may add latency or minimum storage durations. Standard suits hot, frequently accessed data. Infrequent Access lowers storage cost for data read occasionally but charges more per retrieval. Archive tiers like Glacier are cheapest to store but can take minutes to hours to restore and carry retrieval fees and minimum retention periods. To automate, attach lifecycle rules that transition objects by age, for example move to Infrequent Access after thirty days and to Archive after ninety, and expire them later. When access is unpredictable, use an intelligent-tiering class that monitors each object and moves it automatically, so you avoid retrieval surprises. Always factor per-object transition costs and minimum-duration charges so tiering down does not cost more than it saves on small or short-lived objects.

COMMON WRONG ANSWERS Archiving data that is still read often, then paying steep retrieval fees and waiting on restores. Forgetting minimum-duration charges, where moving tiny objects to a colder tier costs more than it saves. Ignoring archive restore latency in a workflow that needs immediate access. Hand-moving objects instead of using lifecycle automation.

LIKELY FOLLOW-UPS When is intelligent tiering better than fixed lifecycle rules. What are the retrieval-time options for archive tiers. How do minimum-duration charges affect small objects. How do you measure access patterns to choose thresholds.

ONE CONCRETE EXAMPLE A logging platform keeps logs in Standard for thirty days for active debugging, transitions them to Infrequent Access for ninety days where audits occasionally read them, then moves them to an archive tier for seven-year compliance retention, and finally expires them. Lifecycle rules do this automatically, and because the team confirmed logs are rarely read after thirty days, the colder tiers cut storage cost sharply without painful retrieval surprises.