Which solution should be recommended to continually copy performance data from Azure Blob Storage to an Azure SQL database?

Azure Data Factory is the most suitable solution for continually copying performance data from Azure Blob Storage to an Azure SQL Database. It is designed specifically for data integration and workflow automation, allowing users to create data pipelines that can ingest data from various sources and load it into different destinations, like an Azure SQL Database.

With Azure Data Factory, users can schedule and automate data movement and transformation, which is crucial for continual synchronization of performance data. It supports complex data workflows, and allows for data transformation as needed during the transfer process, ensuring that the data in the SQL database is not only copied but is also ready for analysis and reporting.

The other options do not align with the requirement to continually copy data. Data Migration Assistant (DMA) is primarily used for assessing and migrating databases to Azure, especially when moving from on-premises to the cloud. It is not intended for ongoing data transfer. Azure Data Box facilitates the transfer of large amounts of data to Azure but is not designed for continuous data replication or streaming. Lastly, Azure Database Migration Service helps in the migration of databases to Azure but, similarly to DMA, does not facilitate continuous data copying.

Therefore, Azure Data Factory is uniquely positioned to meet the need for ongoing data integration from Azure Blob Storage to Azure SQL Database