Blob access tiers: hot vs cool vs cold vs archive
Verdict: Frequent reads, hot tier. Infrequent with a 30-day minimum, cool. Infrequent with a 90-day minimum, cold. Rarely accessed with a 180-day minimum, offline and rehydrated before reading, archive.
| Criterion | Hot tier | Cool tier | Cold tier | Archive tier |
|---|---|---|---|---|
| Access pattern | Frequent | Infrequent | Infrequent | Rare |
| Minimum storage | No minimum | 30 days | 90 days | 180 days |
| State | Online | Online | Online | Offline, rehydrate to read |
| Cost profile | Highest storage, lowest access | Lower storage, higher access | Lower storage still | Lowest storage, highest retrieval |
Rules
- Choose the hot tier for frequently accessed working data: highest storage cost but lowest access cost.
- Choose the cool tier for infrequently accessed data stored at least 30 days, kept online.
- Choose the archive tier for rarely accessed data kept at least 180 days; it is offline and must be rehydrated before reading, at the lowest storage cost.
Traps
- The cold tier's minimum is 90 days, so it does not fit a 30-day requirement; that is the cool tier.
- Archive is offline with rehydration latency, so it cannot serve constantly read blobs; that is the hot tier.