Backup Snapshots - Application-Aware, File System Consistent, Crash-Consistent

First, see the tables of supported quenching mechanisms for various guest operating systems. Directly on the official VMware website.

See also:

VMware Knowledge Base

In this article, you will get information about backup snapshots. In Xopero ONE you can enable the application-aware backup for machines with Windows Server system. Otherwise, the system will use file-system consistent backup by default for machines with Windows system. Only crash-consistent backups are supported on Linux system.

Backup snapshots - application-aware, file system consistent, crash-consistent

Application-aware

In Xopero ONE, when you creating or editing your VMware backup plan, you can enable application-aware backup option (only available on Windows Server versions). This will allow you to create transactionally consistent backups or replicas of Virtual Machines.

This functionality is based on Microsoft VSS service. The Volume Shadow Copy service silences the application and pauses write requests (up to 60 seconds). VSS flushes the file system buffer and then freezes the file system, which ensures that file system metadata is written and that the data is written in a consistent order.

See also:

How Volume Shadow Copy Service Works: Data Recoverydocsmsft

File system consistent

File-system consistent backups provide consistency by taking a snapshot of all files at the same time. To make an application-consistent Snapshot copy, you should halt the application before the Snapshot operation. To ensure that a Snapshot copy is application-consistent, you might need to stop or perform the necessary steps to quiesce the application before taking the Snapshot copy.

Crash-consistent

Crash-consistent backups allow for consistent backups of files on disk. A crash-consistent backup takes a snapshot of all the files at the exact same time. This means that any files that rely on each other are at the same point in time, and thus they are consistent. The very term “crash-consistent” refers to the fact that capturing the backup is like capturing a restore point at the instant leading up to the server crashing or being powered off or reset.