Hi @ David Leslie •,
Welcome to Microsoft Q&A Platform.
Should the Storage Account Access Tier be changed to Cool?
Yes — for backup files that are kept only 7 days and accessed rarely, the Cool access tier is the cost-optimal choice. Cool reduces storage cost without impacting restore speed (unlike Archive). and move existing blobs can also be moved to Cool if needed.
Can we check whether blob snapshots or versions exist and are adding hidden cost?
Yes, as states in Pricing and billing, Blob snapshots, like blob versions, are billed at the same rate as active data, Microsoft recommends managing your snapshots carefully to avoid extra charges.
Delete and re-create snapshots associated with a blob whenever you update the blob.
Can Lifecycle Management rules safely delete backup files older than 7 days?
Yes, The Lifecycle will delete the current versions of a blob, previous versions of a blob, or blob snapshots at the end of their lifecycles. Ref: Azure Blob Storage lifecycle management
Note: Ensure only one automated cleanup mechanism is active (either PowerShell or Lifecycle) otherwise you risk conflict or race conditions.
Should other settings be adjusted (account-level vs. blob-level)?
- The account access tier is set correctly (Cool)
- All backups are uploaded at the correct blob tier (inherit from account unless explicitly overridden)
- Lifecycle rules are applied at the correct container
- No settings like soft-delete, versioning, or snapshots conflict with cleanup rules
I hope this information helps to address all your question's.
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