What consistency level of backup captures memory content during Azure VM backups?

The choice of app-consistent backup as the correct answer is based on the understanding of how Azure VM backups function in relation to applications running on those virtual machines. An app-consistent backup captures the state of the data in memory, ensuring that all transactions are completed, and that the application's data is in a consistent state. This is especially crucial for applications that involve multiple transactions, as it prevents potential data loss or corruption.

During an app-consistent backup, Azure employs mechanisms such as Volume Shadow Copy Service (VSS) to facilitate the coordination between the backup process and the application, allowing the application to prepare for backup by flushing any in-memory data to disk. This ensures that the backup reflects the most current state of the application and its data, making it safe to restore to that point in time.

In contrast, other backup consistency levels like file-consistent and crash-consistent do not ensure that applications complete all in-progress transactions. File-consistent only ensures files are in a consistent state from the perspective of the file system, while crash-consistent represents a state as if the VM experienced an unplanned shutdown, without guarantee regarding application data integrity. Storage-consistent refers to the storage level and does not provide a view of application or operating system states