1## Azure Storage Cost Optimization
2 
3Reference guide for identifying cost savings opportunities in Azure Storage accounts through tier analysis, lifecycle policies, and orphaned resource detection.
4 
5## Subscription Input Options
6 
7Accept any of these identifiers to identify subscriptions for analysis:
8 
9| Input Type | Example | Use Case |
10|------------|---------|----------|
11| **Subscription ID** | `a1b2c3d4-...` | Analyze specific subscription |
12| **Subscription Name** | `Production-Environment` | User-friendly identifier |
13| **Subscription Prefix** | `StorageTeam -` | Analyze all team subscriptions |
14| **Tenant ID** | `tenant-guid` | Analyze entire organization |
15| **"All my subscriptions"** | (keyword) | Scan all accessible subscriptions |
16 
17## Cost Optimization Rules
18 
19When analyzing each storage account, apply these prioritized rules:
20 
21| Priority | Rule | Detection Logic | Recommendation | Avg Savings |
22|----------|------|----------------|----------------|-------------|
23| 🔴 Critical | Orphaned Managed Disks (Compute) | Managed disks with `managedBy` empty (billed as storage) | Delete or snapshot and delete | $20-500/mo |
24| 🔴 Critical | Premium in Dev | `sku.name` contains `Premium` AND `tags.environment in ['dev','test','staging']` | Downgrade to Standard | $50-400/mo |
25| 🟠 High | No Lifecycle Policy | Blob service has no lifecycle management rules configured | Add tiering/deletion rules | $50-300/mo |
26| 🟠 High | Hot-Only with Infrequent Access | >80% of blobs unaccessed for 30+ days AND all in Hot tier | Move to Cool or enable auto-tiering | $30-200/mo |
27| 🟠 High | GRS in Non-Production | `sku.name` contains `GRS` or `GZRS` AND `tags.environment in ['dev','test']` | Downgrade to LRS or ZRS | $40-300/mo |
28| 🟠 High | Classic Storage Accounts | `kind == 'Storage'` (classic/v1) | Upgrade to StorageV2 for tiering support | Variable |
29| 🟡 Medium | Large Snapshots | Snapshot cost exceeds 20% of base blob cost | Review snapshot retention policy | $20-100/mo |
30| 🟡 Medium | Soft Delete Retention >30 days | `deleteRetentionPolicy.days > 30` | Reduce to 7-14 days unless compliance requires it | $10-50/mo |
31| 🟡 Medium | No Access Tier Set | Blobs using default Hot when Cool would suffice | Set explicit Cool or Cold tier | $20-100/mo |
32| 🟡 Medium | Unused Containers | Containers with zero blobs or zero access for 90+ days | Delete or archive contents | $5-50/mo |
33| 🟢 Low | Untagged Storage Account | Missing required tags (`environment`, `owner`, `costCenter`) | Apply tags for cost allocation | N/A |
34| 🟢 Low | Old Storage Account | Age >365 days without review | Verify still needed | Variable |
35| 🟢 Low | Version-Heavy Blobs | Blob versioning enabled with >50 versions per blob | Add version deletion lifecycle rule | $5-30/mo |
36 
37## Access Tier Decision Matrix
38 
39| Last Access | Data Size | Access Pattern | Recommended Tier |
40|-------------|-----------|----------------|-----------------|
41| <30 days | Any | Frequent reads/writes | Hot |
42| 30-90 days | Any | Occasional reads | Cool |
43| 90-180 days | Any | Rare reads, compliance | Cold |
44| >180 days | Any | Archival, legal hold | Archive |
45 
46> **Note**: Archive tier has retrieval costs and rehydration delays (hours). Only use for data that rarely needs access.
47 
48## Lifecycle Policy Template
49 
50Recommend this baseline policy for accounts without lifecycle management:
51 
52```json
53{
54  "rules": [
55    {
56      "name": "move-to-cool-after-30-days",
57      "type": "Lifecycle",
58      "definition": {
59        "actions": {
60          "baseBlob": {
61            "tierToCool": { "daysAfterLastAccessTimeGreaterThan": 30 }
62          }
63        },
64        "filters": { "blobTypes": ["blockBlob"], "prefixMatch": [] }
65      }
66    },
67    {
68      "name": "move-to-archive-after-180-days",
69      "type": "Lifecycle",
70      "definition": {
71        "actions": {
72          "baseBlob": {
73            "tierToArchive": { "daysAfterLastAccessTimeGreaterThan": 180 }
74          }
75        },
76        "filters": { "blobTypes": ["blockBlob"], "prefixMatch": [] }
77      }
78    },
79    {
80      "name": "delete-old-snapshots",
81      "type": "Lifecycle",
82      "definition": {
83        "actions": {
84          "snapshot": {
85            "delete": { "daysAfterCreationGreaterThan": 90 }
86          }
87        },
88        "filters": { "blobTypes": ["blockBlob"] }
89      }
90    },
91    {
92      "name": "delete-old-versions",
93      "type": "Lifecycle",
94      "definition": {
95        "actions": {
96          "version": {
97            "delete": { "daysAfterCreationGreaterThan": 90 }
98          }
99        },
100        "filters": { "blobTypes": ["blockBlob"] }
101      }
102    }
103  ]
104}
105```
106 
107> ⚠️ **Important**: Lifecycle policies that use `daysAfterLastAccessTimeGreaterThan` require **last access time tracking** to be enabled on the storage account. Verify with: `az storage account blob-service-properties show --account-name <name> --resource-group <rg> --query lastAccessTimeTrackingPolicy`
108 
109## Resource Graph Queries
110 
111**Find storage accounts without lifecycle policies:**
112 
113Use Azure CLI to check lifecycle policy presence (not queryable via Resource Graph):
114 
115```bash
116az storage account management-policy show --account-name <name> --resource-group <rg>
117```
118 
119**Find Premium storage accounts in non-production:**
120 
121```kql
122Resources
123| where type =~ 'microsoft.storage/storageaccounts'
124| where sku.name contains 'Premium'
125| where tags.environment in~ ('dev', 'test', 'staging', 'sandbox')
126| project name, resourceGroup, sku=sku.name, tags
127```
128 
129**Find GRS/GZRS accounts in dev/test (redundancy downgrade candidates):**
130 
131```kql
132Resources
133| where type =~ 'microsoft.storage/storageaccounts'
134| where sku.name contains 'GRS' or sku.name contains 'GZRS'
135| where tags.environment in~ ('dev', 'test', 'staging')
136| project name, resourceGroup, sku=sku.name, location, tags
137```
138 
139**Find classic (v1) storage accounts:**
140 
141```kql
142Resources
143| where type =~ 'microsoft.storage/storageaccounts'
144| where kind =~ 'Storage'
145| project name, resourceGroup, location, kind
146```
147 
148**Find orphaned managed disks (unattached):**
149 
150```kql
151Resources
152| where type =~ 'microsoft.compute/disks'
153| where isempty(managedBy)
154| project name, resourceGroup, location, diskSizeGb=properties.diskSizeGB, sku=sku.name
155```
156 
157## Report Templates
158 
159### Subscription-Level Summary
160Include: subscription name/ID, total monthly storage cost, account count by SKU/tier, total data stored (TB), top issues found.
161 
162### Detailed Storage Account Analysis
163Include: account name, resource group, SKU/redundancy, kind, monthly cost, capacity (GB), access tier distribution (%), lifecycle policy status, and optimization recommendations.
164 
165## Tools & Commands
166 
167**MCP Tool:** `azure__storage` with sub-commands for account and container operations
168 
169**Azure CLI:**
170- `az storage account list --subscription <id>` - List accounts
171- `az storage account show --name <name> --resource-group <rg>` - Get details
172- `az storage account management-policy show --account-name <name> --resource-group <rg>` - Check lifecycle policy
173- `az storage account blob-service-properties show --account-name <name> --resource-group <rg> --query lastAccessTimeTrackingPolicy` - Check access tracking
174- `az monitor metrics list --resource <id> --metric UsedCapacity` - Capacity metrics
175- `az monitor metrics list --resource <id> --metric Transactions --dimension ApiName` - Access patterns
176 
177## Pricing Quick Reference
178 
179Tiers ranked by storage cost (East US, LRS, approximate):
180- **Hot**: $0.018/GB/mo (cheapest reads)
181- **Cool**: $0.01/GB/mo (30-day minimum retention)
182- **Cold**: $0.0036/GB/mo (90-day minimum)
183- **Archive**: $0.002/GB/mo (180-day minimum, hours to rehydrate)
184 
185Always validate from [official pricing](https://azure.microsoft.com/pricing/details/storage/blobs/).
186 
187**Redundancy savings**: Downgrading from GRS to LRS saves ~50%. Dev/test rarely needs GRS/GZRS.
188