Access Tier
A setting on blob storage that determines the cost and retrieval latency of stored data, offered as Hot (frequent access), Cool (infrequent, 30+ day retention), and Archive (rare access, hours-long rehydration).
Access Tier
Access tiers let you pay less for storage in exchange for slower or costlier retrieval.
Why It Matters in Production
Zerodha keeps the last 90 days of trade confirmation PDFs in Hot tier for instant download, moves 90-day to 3-year-old records to Cool, and archives anything older than 3 years to Archive tier for regulatory retention.
az storage blob set-tier --account-name zerodhaprodstorage \ --container-name trade-confirmations \ --name 2023/jan/confirmation-8821.pdf --tier ArchiveCommon MistakeSetting rarely-accessed logs to Cool tier but forgetting the early-deletion penalty — Cool has a minimum 30-day retention charge even if deleted sooner.
Frequently Asked Questions
How is Archive tier different from just deleting old blobs?
Archive tier keeps data available for compliance or occasional recovery at a fraction of Hot-tier storage cost, but it's offline storage — there's no instant read. Rehydrating a blob back to Hot or Cool for access takes anywhere from about an hour (high-priority rehydration) up to 15 hours (standard priority), so it's meant for data you're legally required to retain but essentially never touch, not for anything on a recovery-time deadline.
What's a common mistake with Access Tiers?
Setting a blob to Archive and then having an application try to read it directly — that read fails until rehydration completes, which can silently break a workflow expecting immediate access. Also, moving data between tiers isn't free: early-deletion penalties apply if you move data out of Cool or Archive before a minimum retention period, so lifecycle policies should be tuned to actual access patterns, not just cost-optimized blindly.