Azure Storage costs are $30K/month. Implement tiering and lifecycle policies.

Step 1: Analyze Current Usage

# Get storage account metrics
az monitor metrics list \
  --resource /subscriptions/{sub}/resourceGroups/{rg}/providers/Microsoft.Storage/storageAccounts/proddata \
  --metric "BlobCount,BlobCapacity" \
  --interval PT1H \
  --start-time 2024-01-01 \
  --end-time 2024-01-31

# List blobs with last access time
az storage blob list \
  --account-name proddata \
  --container-name logs \
  --query "[].{name:name,tier:properties.blobTier,lastAccess:properties.lastAccessedOn,size:properties.contentLength}" \
  --output table

# Enable last access time tracking
az storage account blob-service-properties update \
  --account-name proddata \
  --resource-group myRG \
  --enable-last-access-tracking true

Step 2: Understand Azure Storage Tiers

Step 3: Implement Lifecycle Policies

{
  "rules": [
    {
      "enabled": true,
      "name": "logs-lifecycle",
      "type": "Lifecycle",
      "definition": {
        "filters": {
          "blobTypes": ["blockBlob"],
          "prefixMatch": ["logs/"]
        },
        "actions": {
          "baseBlob": {
            "tierToCool": {
              "daysAfterModificationGreaterThan": 7
            },
            "tierToCold": {
              "daysAfterModificationGreaterThan": 30
            },
            "tierToArchive": {
              "daysAfterModificationGreaterThan": 90
            },
            "delete": {
              "daysAfterModificationGreaterThan": 365
            }
          }
        }
      }
    },
    {
      "enabled": true,
      "name": "backups-lifecycle",
      "type": "Lifecycle",
      "definition": {
        "filters": {
          "blobTypes": ["blockBlob"],
          "prefixMatch": ["backups/"]
        },
        "actions": {
          "baseBlob": {
            "tierToCool": {
              "daysAfterModificationGreaterThan": 1
            },
            "tierToArchive": {
              "daysAfterModificationGreaterThan": 30
            },
            "delete": {
              "daysAfterModificationGreaterThan": 2555
            }
          }
        }
      }
    },
    {
      "enabled": true,
      "name": "cleanup-snapshots",
      "type": "Lifecycle",
      "definition": {
        "filters": {
          "blobTypes": ["blockBlob"]
        },
        "actions": {
          "snapshot": {
            "tierToCool": {
              "daysAfterCreationGreaterThan": 30
            },
            "delete": {
              "daysAfterCreationGreaterThan": 90
            }
          }
        }
      }
    }
  ]
}

# Apply lifecycle policy
az storage account management-policy create \
  --account-name proddata \
  --resource-group myRG \
  --policy @lifecycle-policy.json

Step 4: Bicep Implementation

resource storageAccount 'Microsoft.Storage/storageAccounts@2023-01-01' = {
  name: 'proddata'
  location: location
  sku: {
    name: 'Standard_LRS'
  }
  kind: 'StorageV2'
  properties: {
    accessTier: 'Hot'  // Default tier for new blobs
    allowBlobPublicAccess: false
    minimumTlsVersion: 'TLS1_2'
  }
}

resource blobServices 'Microsoft.Storage/storageAccounts/blobServices@2023-01-01' = {
  parent: storageAccount
  name: 'default'
  properties: {
    lastAccessTimeTrackingPolicy: {
      enable: true
      name: 'AccessTimeTracking'
      trackingGranularityInDays: 1
      blobType: ['blockBlob']
    }
  }
}

resource lifecyclePolicy 'Microsoft.Storage/storageAccounts/managementPolicies@2023-01-01' = {
  parent: storageAccount
  name: 'default'
  properties: {
    policy: {
      rules: [
        {
          enabled: true
          name: 'logs-tier-and-delete'
          type: 'Lifecycle'
          definition: {
            filters: {
              blobTypes: ['blockBlob']
              prefixMatch: ['logs/']
            }
            actions: {
              baseBlob: {
                tierToCool: {
                  daysAfterLastAccessTimeGreaterThan: 7
                }
                tierToCold: {
                  daysAfterLastAccessTimeGreaterThan: 30
                }
                tierToArchive: {
                  daysAfterLastAccessTimeGreaterThan: 90
                }
                delete: {
                  daysAfterLastAccessTimeGreaterThan: 365
                }
              }
            }
          }
        }
        {
          enabled: true
          name: 'media-optimization'
          type: 'Lifecycle'
          definition: {
            filters: {
              blobTypes: ['blockBlob']
              prefixMatch: ['media/']
            }
            actions: {
              baseBlob: {
                tierToCool: {
                  daysAfterLastAccessTimeGreaterThan: 30
                }
              }
            }
          }
        }
      ]
    }
  }
}

Step 5: Use Cold Tier for Additional Savings

# Cold tier (new in 2023) offers better economics than Cool for 90+ day retention
# Cold: $0.0036/GB storage, higher access costs
# Cool: $0.01/GB storage, lower access costs

# Break-even: ~2 reads per blob per month

# Move existing blobs to Cold
az storage blob set-tier \
  --account-name proddata \
  --container-name backups \
  --name "backup-2023-01.zip" \
  --tier Cold

Step 6: Archive Tier for Compliance Data

# Archive tier: $0.00099/GB but requires rehydration
# Rehydration time: Standard (up to 15 hours), High priority (< 1 hour)

# Set blob to Archive
az storage blob set-tier \
  --account-name proddata \
  --container-name compliance \
  --name "audit-2020.zip" \
  --tier Archive

# Rehydrate when needed
az storage blob set-tier \
  --account-name proddata \
  --container-name compliance \
  --name "audit-2020.zip" \
  --tier Hot \
  --rehydrate-priority High

Step 7: Monitor and Optimize

// Alert on unexpected Hot tier growth
resource storageAlert 'Microsoft.Insights/metricAlerts@2018-03-01' = {
  name: 'hot-tier-growth-alert'
  location: 'global'
  properties: {
    description: 'Alert when Hot tier capacity grows unexpectedly'
    severity: 2
    enabled: true
    scopes: [storageAccount.id]
    evaluationFrequency: 'PT1H'
    windowSize: 'PT6H'
    criteria: {
      'odata.type': 'Microsoft.Azure.Monitor.SingleResourceMultipleMetricCriteria'
      allOf: [
        {
          name: 'HotCapacityGrowth'
          metricName: 'BlobCapacity'
          dimensions: [
            {
              name: 'Tier'
              operator: 'Include'
              values: ['Hot']
            }
          ]
          operator: 'GreaterThan'
          threshold: 15000000000000  // 15TB threshold
          timeAggregation: 'Average'
        }
      ]
    }
    actions: [
      {
        actionGroupId: actionGroup.id
      }
    ]
  }
}

Cost Calculation

BEFORE:
- All 60TB in Hot tier
- Storage: 60TB × $0.0184 = $1,104/month
- Transactions + egress: ~$28,896/month
- Total: ~$30,000/month

AFTER (with lifecycle policies):
logs/ (30TB):
  - 2TB Hot (current week): $37
  - 5TB Cool (week 2-4): $50
  - 10TB Cold (month 2-3): $36
  - 13TB Archive (older): $13
  Subtotal: $136

backups/ (20TB):
  - 1TB Cool (current month): $10
  - 19TB Archive: $19
  Subtotal: $29

media/ (10TB):
  - 8TB Hot: $147
  - 2TB Cool: $20
  Subtotal: $167

Storage Total: $332/month (was $1,104)
Transactions reduced ~40%: $17,338
Total: ~$17,670/month

SAVINGS: ~$12,330/month (41% reduction)