Subclient Properties (Backup Options)
Perform application consistent backup
This option is selected by default. When you back up a virtual machine under the subclient, the operating system and applications are quiesced on the virtual machine to enable the state of active applications on the VM to be captured. The backup process may be slower because of the time needed to quiesce applications, capture any transactions that occur while the VM is offline, and update applications with pending transactions.
Application consistent backups are typically required for virtual machines hosting high transaction applications, such as applications that rely on frequent database updates. Application consistent backups require Hyper-V Integration Services and Volume Shadow Copy Service (VSS) on the virtual machine.
Perform crash consistent backup
Select this option to capture only stored data for virtual machine backups under the subclient, without taking virtual machines offline during the backup. This option can be used for non-Windows virtual machines, legacy Windows virtual machines, and Windows virtual machines that do not require application consistent backups. A crash consistent backup can also be used when backups fail because of VSS errors; running a crash consistent backup ensures that virtual machines are backed up, even when VSS cannot be engaged successfully.