What are the main Azure Storage options, and how do access tiers and redundancy work?
What they are really testing: Whether you can match storage type to use case (Blob vs Files vs Disks) and reason about cost via tiers and durability via redundancy (LRS/ZRS/GRS). Practical cost and resilience design.
A real interview question
What are the main Azure Storage options, and how do access tiers and redundancy work?
What most people say
drag me
“You use Blob storage for files and pick how many copies you want.”
It collapses several distinct services (Blob vs Files vs Disks) and treats redundancy as "number of copies" without the zone-versus-region distinction or access tiers, which are the levers for cost and resilience.
The follow-ups they ask next
What is the difference between ZRS and GRS?
ZRS replicates across availability zones within one region (survives a zone outage); GRS replicates to a paired secondary region (survives a regional outage). ZRS for in-region HA, GRS for geo-DR, often combined as GZRS.
When would you use the Archive tier?
For data you rarely access but must retain (compliance, long-term backups). Storage is very cheap, but retrieval has cost and latency (rehydration), so it is wrong for anything needed quickly.
What the interviewer is listening for
- Distinguishes Blob/Files/Disks/Queue/Table
- Knows access tiers trade storage vs access cost
- Knows LRS/ZRS/GRS by failure domain
What sinks the answer
- Treats all storage as "Blob"
- Redundancy as just "copies"
- No zone-vs-region distinction
If you genuinely do not know
Say this instead of freezing. Reasoning out loud from what you do know beats silence every single time, and a good interviewer is listening for exactly that.
“Types: [Blob (objects), Files (SMB/NFS shares), Disks (VM block), Queue/Table]. Blob access tiers: [Hot/Cool/Cold/Archive, colder = cheaper storage but pricier/slower access], tier by access frequency. Redundancy by failure domain: [LRS (one datacenter), ZRS (across zones), GRS/GZRS (paired region)]. Match [type to workload, tier to access, redundancy to the failure you must survive].”
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