Simple definition
A crash-consistent backup captures storage state without application coordination, resembling an unexpected power loss.
Purpose and use
A crash-consistent point captures storage state comparable to an abrupt shutdown, without full application coordination.
How does it work?
It preserves available blocks at the selected moment; memory-only data and unfinished application operations can require recovery.
Example and verification
During testing, verify operating-system startup and then application opening and consistency, especially for transactional databases.
Points to watch
A system that boots does not prove that all recent transactions survived. Recovery also depends on application logs and recovery mechanisms.
In short
Storage consistency and application consistency are separate levels that a backup plan must distinguish.