Standard File Shares Left on the Transaction Optimized Tier

Transaction optimized has the highest at-rest storage price and the lowest transaction prices. Microsoft recommends creating shares on transaction optimized for the initial migration, because migration is transaction-heavy, and then choosing the right tier once normal usage is known. The second step is often skipped, and the share stays on transaction optimized indefinitely.

Most file shares settle into a pattern dominated by stored capacity rather than transactions, such as departmental shares, archives, application content and lift-and-shift file servers. On transaction optimized they pay the highest per-GiB rate every month for transaction pricing they no longer need. The Well-Architected guide for Azure Files states that most customers should choose cool even if they actively use the share. This is the opposite case to busy shares placed on cool, which pay excessive transaction charges.

Pay-as-you-go shares are billed on used capacity and transactions, with the balance set by the access tier.

Data stored

Billed per used GiB-month, including differential snapshots and soft-deleted shares; highest on transaction optimized, lower on hot, lowest on cool

Transactions

Billed per bucket of 10,000 write, list, read, other and delete operations; lowest on transaction optimized, higher on hot, highest on cool

Metadata and data retrieval

Hot and cool also bill file system metadata per GiB, and cool bills data retrieval per GiB read

Tier change

Moving to a cooler tier incurs one write transaction per file at the destination tier's price; tiers can be changed up to five times in 30 days and not twice within 24 hours

• List file shares in general-purpose v2 storage accounts whose accessTier is TransactionOptimized, and note when each was created or migrated
• In Cost Management, split each storage account's Azure Files cost by meter; accounts where the Data Stored meter dominates and the Write, List, Read and Other Operations meters are a small fraction are candidates for hot or cool
• Chart the File metric namespace Transactions metric (Sum, split by API Name) over a period that excludes the migration window, and multiply to a monthly figure
• Enter the used capacity and monthly transaction counts into the pricing calculator for each of the three tiers to find the cheapest one
• Where several shares share one storage account, remember that pay-as-you-go transaction data is reported only at the storage account level, so per-share estimates are approximate

• Change the access tier of capacity-dominated shares to cool (or hot where transactions are moderate) once migration traffic has ended and a few weeks of normal usage have been measured
• Budget for the one-time tier change charge of one write transaction per file, and change tiers only when the access pattern changes, since each move incurs transactions and moving back out of cool also incurs data retrieval
• Place one share per storage account where practical so transaction metrics and billing are visible per share, as Microsoft recommends
• For new deployments, consider the provisioned v2 HDD model, which Microsoft recommends for new classic file shares and which does not bill per transaction
• Revisit tier choices periodically, and use the transaction-heavy guidance in the opposite direction if a share becomes busy

• Understand Azure Files Billinglearn.microsoft.com
• Architecture Best Practices for Azure Files - Microsoft Azure Well-Architected Frameworklearn.microsoft.com
• Azure Files Pricingazure.microsoft.com