What is a requirement for the name of a storage account in Azure?

The requirement that a storage account name in Azure must be globally unique is essential because Azure stores all storage account names across all regions and subscriptions. This means that no two storage accounts can share the same name, regardless of their location or the subscription they belong to. This global uniqueness ensures that when resources like blobs, files, queues, and tables are accessed through the storage account, there is no confusion or conflict between accounts, which could lead to data access issues.

To elaborate on other aspects: while the storage account name does need to be unique within a subscription, this is not sufficient since uniqueness in one subscription might lead to conflicts in another. Additionally, requiring the name to include numbers or be unique within a resource group is not a mandated rule for Azure storage account naming; such criteria can vary and would not meet the essential global uniqueness principle.