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Understanding Azure Storage Mover billing

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Azure Storage Mover facilitates the migration of unstructured data into Azure. This article provides insight into the categories of costs that may apply to your migration scenarios.

Billing components

In a migration to Azure, there are several components involved that can affect your bill:

  1. Storage Mover service usage
  2. Target storage usage
  3. Network usage

1. Storage Mover service usage

All current features of the Azure Storage Mover service are provided free of charge. However, service enhancements and other features may be included in future releases. It's possible that the use of these features may incur a charge.

2. Target Azure storage usage

As you begin your migration into Azure, the service copies your files and folders into your target Azure Storage locations. Depending on the configuration of these storage targets, usage charges may apply.

Any storage usage charges incurred are the result of the following factors:

  • Storage transactions
  • Billed capacity

The billing model for each Azure Storage target determines how these charges apply. There are two different billing models in Azure Storage:

  • Storage transactions caused by the Storage Mover service are billed. Review your specific storage product's pricing pages for details on transaction charges. The estimating storage transaction charges section of this article explains why it can be difficult to estimate a migration’s effect on your storage transaction charges.
  • One advantage of the consumption-based model is that capacity charges are progressively applied. Charges are incurred only as files are migrated and increasingly more storage capacity is consumed. This model helps prevent storage preprovisioning or over-provisioning ahead of a migration.

Note

A typical cloud migration has multiple sources and multiple Azure storage targets. Both billing models may apply to you across your migration projects.

Estimating storage transaction charges

Storage transactions aren't billable for every Azure Storage type. Review the previous section and your specific storage product's pricing pages.

If you've determined that your Azure storage product charges for transactions, it may be difficult to estimate the number generated by your migration.

  • It's not possible to estimate the number of transactions based on the utilized storage capacity of the source. The number of transactions scales with the number of namespace items (files and folder) and their properties that are migrated, not their size. For example, more transactions are required to migrate 1 GiB of small files than 1 GiB of larger files.
  • An empty Azure target requires fewer resources than a target that already contains items. To comply with your migration's settings, the Storage Mover agent often needs to enumerate a target's existing namespace. This enumeration increases the number of transactions.
  • In order to minimize downtime, you may need to run copy operations several times between a source and its target. All source and target items are processed during each copy operation, though subsequent runs finish faster. After the initial operations, only the differences introduced between copy runs are transported over the network. It's important to understand that although less data is being transported, the number of transactions required may remain the same.
  • Copying the same file twice might not result in the same number of transactions. Processing an item migrated in a previous copy run may result in only a few read transactions. In contrast, changes to metadata or content between copy runs may require a larger number of transactions to update the target. Each file in your namespace may have unique requirements, resulting in a different number of transactions.

3. Network usage

Upload bandwidth is another factor that could affect overall cost. The bandwidth utilized by your migration carries the same charge as any other Azure-bound traffic. There's no Storage Mover-specific premium. Your specific network connection and provider agreements determine whether upload charges are incurred.

Next steps

After understanding the billing implications of your cloud migration, it's a good idea to get more familiar with the Storage Mover service. Select an article to learn more.