Understand Azure Files Billing
Here’s a concise, structured summary of the article “Understand Azure Files billing models.” I preserved the original meaning and links where applicable.
Overview
Azure Files cost depends on four main factors:
Billing model: provisioned v2 (recommended), provisioned v1, or pay-as-you-go.
Media tier: SSD (premium) or HDD (standard).
Redundancy: LRS (Local), ZRS (Zone), GRS (Geo, HDD only), GZRS (GeoZone, HDD only).
Usage of value-added services (Azure File Sync, Azure Backup, Microsoft Defender for Storage), which add licensing, transaction, and Azure Files costs.
Pricing details: https://azure.cn/pricing/details/storage/files/
Storage units
Uses base-2 units: KiB, MiB, GiB, TiB (commonly mislabeled as KB/MB/GB/TB by some OSes).
OS labeling varies (Windows uses base-2 but labeled as base-10; macOS uses base-10).
File share total cost of ownership checklist
Compare billing models (provisioned vs pay-as-you-go).
Confirm resiliency and redundancy requirements.
Consider management overhead (Azure Files is fully managed).
Include costs of value-added services (licensing, their own transactions, and added Azure Files resource usage).
Provisioned v2 (recommended)
Predictable billing: you provision storage (GiB), IOPS, and throughput (MiB/s) and pay for what you provision.
Can scale up/down; decreases allowed only after 24 hours from last increase.
Default IOPS/throughput recommendations based on provisioned storage; you can override.
Bursting: credit-based IOPS bursting (accrual/decline/constant states). Burst limits and credits computed via given formulas.
Snapshots: differential; if snapshot differential + live data > provisioned storage, excess billed as Overflow Snapshot Usage (formula provided).
Soft delete: deleted shares while retained are billed for used storage during retention; provisioned quotas still count toward account limits (but not billed).
Billing meters: Provisioned Storage, Provisioned IOPS, Provisioned Throughput MiBPS, Overflow Snapshot Usage, Soft-Deleted Usage. Consumption emitted hourly.
Migration guidance:
Without Azure File Sync: Migrate files between shares (link).
With Azure File Sync: Use share-to-share migration guidance (link).
Availability and resource models: table-driven combinations of media, redundancy, protocol and storage-account SKUs (see article for full tables and limits).
Provisioned v1
Provisioned storage determines IOPS/throughput in fixed ratio (SSD only). Similar lifecycle rules to v2 (dynamic scale with 24-hour decrease restriction).
Baseline IOPS and throughput computed by formulas; to get more performance you must provision more storage.
Bursting: credit-based, with formulas and examples provided.
Snapshots: differential; snapshot storage billed to a used-snapshot meter (reduced price vs provisioned storage).
Soft delete: soft-deleted shares billed based on used storage, emitted against used snapshot storage meter.
Billing meters: Premium Provisioned (GiB) and Premium Snapshots. Consumption emitted hourly/monthly-unit conversions described.
Availability and resource models: SSD-only, specific SKUs required; account limits and planning considerations included.
Pay-as-you-go (HDD-only)
Usage-based billing: charged for used storage, transactions, and data transfer. Less predictable for budgeting.
Access tiers (transaction optimized, hot, cool) affect data-at-rest price and transaction prices—choose based on workload:
Transaction optimized: best for high IOPS; highest storage price, lowest transaction price.
Hot: middle ground.
Cool: lowest storage price, highest transaction price and data retrieval charges.
Transactions: SMB and REST operations translate to multiple transactions. Transactions are categorized (write, list, read, other/protocol, delete) with example operations per category.
Switching access tiers: causes transaction and possibly data retrieval charges; tier changes limited (max 5 changes per 30 days; 24-hour cooldown between changes).
Snapshots and soft-delete: snapshot differential and soft-deleted used storage billed to normal used-storage meter (no separate snapshot line item).
Billing meters: Data Stored, Metadata (hot/cool only), Write/List/Read/Other operations (buckets of 10,000), Data Retrieval (cool only), Geo-Replication Data Transfer (for GRS/GZRS). Consumption patterns and hourly/monthly unit conversions explained.
Availability and resource models: supported SKUs/combinations and storage-account limits listed; planning notes to avoid throttling and to track billing per resource.
Provisioned/quota, logical size, and physical size
Provisioned/quota: maximum allowed size (provisioned affects billing for provisioned models; quota for pay-as-you-go does not directly affect billing).
Logical size: reported “size” (used for enforcement and pay-as-you-go billing).
Physical size: actual allocated size on disk; used for snapshot billing (differential allocation between snapshots).
Value-added services (impact on TCO)
Costs divided into:
Licensing for the service.
Transaction costs from the service.
Additional Azure Files costs caused by the service (storage, transactions, provisioning needs).
Azure File Sync:
Syncs on-prem Windows servers to Azure file share; consider server infrastructure cost, per-server registration fee, Azure Files resource usage (storage, snapshots, IOPS/throughput).
Azure File Sync generates transactions from churn and daily cloud enumeration (one ListFiles per directory per day).
Azure Backup:
Snapshot-based backup for Azure Files; licensing per protected instance (250 GiB unit).
Adds snapshot storage and restore transaction costs.
Microsoft Defender for Storage:
Adds its own transaction-based charges (charged even on provisioned shares). Consider excluding storage accounts with heavy transactions if costs are high.
Operational guidance & planning notes
Account-level limits mean grouping and placement of file shares into storage accounts affects scalability and chargeability; plan headroom for 3–5 years.
Billing granularity is per resource; to track share-level costs, group shares into separate storage accounts as needed.
For pay-as-you-go, to pick access tier, start with transaction optimized during migration, then use actual metrics/pricing calculator to choose best tier.
To view transactions in the portal, follow the Metrics steps (converted into a stepper below).
Steps to see previous transactions (portal)
Navigate to your storage account in the Azure portal.
In the service menu, under Monitoring, select Metrics.
Select Scope as your storage account name, Metric Namespace as "File", Metric as "Transactions", and Aggregation as "Sum".
Select Apply Splitting.
Select Values as "API Name". Set Limit and Sort as desired.
Select your desired time period. Ensure timeframe excludes initial provisioning and is long enough for realistic averages.
Key links
Azure Files pricing: https://azure.cn/pricing/details/storage/files/
Provisioned v2 migration without File Sync: https://docs.azure.cn/en-us/storage/files/migrate-files-between-shares
Provisioned v2 migration with File Sync: https://docs.azure.cn/en-us/storage/file-sync/file-sync-share-to-share-migration
Create a classic file share: https://docs.azure.cn/en-us/storage/files/create-classic-file-share
Pricing calculator: https://azure.cn/pricing/calculator/
If you’d like, I can:
Produce an even shorter one-paragraph TL;DR,
Create a decision checklist (questions and recommended billing model/access tier),
Extract the key formulas and limits into a single quick-reference table. Which would you prefer?
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