Home > Storage > PowerStore > Virtualization and Cloud > Dell PowerStore: VMware vSphere Best Practices > Crash consistent and application consistent snapshots
When taking array-based snapshots of virtual machines, remember that snapshots taken without application coordination are considered crash consistent. Crash consistency is the storage term for data that has a snapshot taken in-progress without application awareness. While most modern applications can recover from crash consistent data, their recovery can yield varying levels of success. For example, when recovering a Microsoft Windows virtual machine, as the operating system boots, it responds as if it has encountered an unexpected power-loss event and can potentially check the disk (chkdsk) on startup.
Application consistent snapshots are supported by products such as Dell AppSync. This enables coordination between the array and the application to help assure that the data is quiesced, the caches are flushed, and the data is preserved in a known good state. Application consistent snapshots such as these offer a higher probability of recovery success.
Note: When taking managed snapshots such as with vVols in PowerStore Manager, virtual machine memory is not included. When performing snapshots from vCenter, we recommend not including virtual machine memory.