Blob Lifecycle Management

What is Lifecycle Management?

Azure Blob Storage Lifecycle Management is a rules engine that automatically manages blobs based on their age or last access time. You define a policy with one or more rules, and Azure applies those rules daily to blobs in your storage account.

Policy Structure

A lifecycle policy consists of one or more rules. Each rule has three parts:

1. Filters

Which blobs does this rule apply to? You can filter by:

• Blob type — blockBlob, appendBlob
• Prefix match — e.g., only blobs in backups/ prefix
• Blob index tags — filter by custom metadata tags

2. Conditions

When should the action trigger? Based on:

• daysAfterModificationGreaterThan — days since blob was last modified
• daysAfterCreationGreaterThan — days since blob was created
• daysAfterLastAccessTimeGreaterThan — days since last access (requires access tracking enabled)

3. Actions

What happens when the condition is met?

• tierToCool — Move to Cool tier
• tierToCold — Move to Cold tier
• tierToArchive — Move to Archive tier
• delete — Permanently delete the blob

Common Lifecycle Patterns

Pattern 1 — Gradual Archive (Most Common)

Blobs are active initially, then used less over time, eventually archived or deleted:

• 0–30 days: Hot (active)
• 30–90 days: Cool (less frequent access)
• 90–365 days: Cold (rare access)
• 365+ days: Archive (compliance only)
• 2555+ days (7 years): Delete

Pattern 2 — Backup Retention

Keep daily backups for 30 days, then delete:

• 0–30 days: Cool
• 30+ days: Delete

Pattern 3 — Log File Management

Application logs: keep recent ones accessible, archive old ones:

• 0–7 days: Hot (being actively queried)
• 7–90 days: Cool
• 90+ days: Archive or Delete

Creating a Policy via Portal

1. Go to your Storage Account in the Azure Portal
2. In the left menu → Data management → Lifecycle management
3. Click + Add a rule
4. Give the rule a name
5. Select Block blobs
6. Set the filter (all blobs or by prefix)
7. Configure the actions — e.g., "Move to cool after 30 days"
8. Add more actions for further transitions
9. Click Add

Creating a Policy via CLI

Lifecycle policies are defined in JSON format:

{
  "rules": [
    {
      "name": "archiveOldBlobs",
      "enabled": true,
      "type": "Lifecycle",
      "definition": {
        "filters": {
          "blobTypes": ["blockBlob"]
        },
        "actions": {
          "baseBlob": {
            "tierToCool": {
              "daysAfterModificationGreaterThan": 30
            },
            "tierToCold": {
              "daysAfterModificationGreaterThan": 90
            },
            "tierToArchive": {
              "daysAfterModificationGreaterThan": 365
            },
            "delete": {
              "daysAfterModificationGreaterThan": 2555
            }
          }
        }
      }
    }
  ]
}

# Apply policy from JSON file
az storage account management-policy create \
  --account-name mystorageaccount2026 \
  --resource-group myResourceGroup \
  --policy @lifecycle-policy.json

Filtering by Prefix

You can apply different lifecycle rules to different "folders" of blobs using prefix filters:

{
  "rules": [
    {
      "name": "backupRetention",
      "enabled": true,
      "type": "Lifecycle",
      "definition": {
        "filters": {
          "blobTypes": ["blockBlob"],
          "prefixMatch": ["backups/"]
        },
        "actions": {
          "baseBlob": {
            "tierToCool": { "daysAfterModificationGreaterThan": 7 },
            "delete": { "daysAfterModificationGreaterThan": 30 }
          }
        }
      }
    },
    {
      "name": "logArchive",
      "enabled": true,
      "type": "Lifecycle",
      "definition": {
        "filters": {
          "blobTypes": ["blockBlob"],
          "prefixMatch": ["logs/"]
        },
        "actions": {
          "baseBlob": {
            "tierToArchive": { "daysAfterModificationGreaterThan": 90 },
            "delete": { "daysAfterModificationGreaterThan": 365 }
          }
        }
      }
    }
  ]
}

Handling Versions and Snapshots

If blob versioning is enabled, lifecycle policies can also manage old versions and snapshots separately from the current blob:

• version actions — apply to non-current versions
• snapshot actions — apply to blob snapshots

"actions": {
  "baseBlob": {
    "tierToArchive": { "daysAfterModificationGreaterThan": 365 }
  },
  "version": {
    "tierToArchive": { "daysAfterCreationGreaterThan": 90 },
    "delete": { "daysAfterCreationGreaterThan": 365 }
  },
  "snapshot": {
    "delete": { "daysAfterCreationGreaterThan": 30 }
  }
}

Real-World Examples

Media Company — Video Archive

A media company uploads new videos daily. Recent videos get lots of views, older ones rarely watched:

• 0–30 days: Hot (new release — high traffic)
• 30–180 days: Cool (catalog — occasional views)
• 180+ days: Cold (archive — very rare views)
• 3+ years: Archive (compliance archive)

Savings: Videos older than 6 months automatically stored at fraction of Hot tier cost.

Healthcare — Patient Records

Patient records must be kept for 7 years (regulatory requirement) but are rarely accessed after initial treatment:

• 0–1 year: Cool (recently treated, may need records)
• 1–7 years: Archive (compliance only)
• 7+ years: Delete (retention period expired)