In what scenario would a crash consistent snapshot be most problematic?

A crash consistent snapshot captures the state of the data at a specific moment in time without coordinating with the applications that are currently running. This can lead to issues, especially in environments where data consistency is critical.

When all applications are online and active, they may be in the middle of transactions or data modifications. If a crash consistent snapshot is taken in this state, there is a risk that some data will be captured in the midst of changes, while other data may not be captured at all, resulting in an inconsistent state. This could lead to data corruption or loss, as there might be dependencies between different pieces of data that are not aligned when the snapshot is taken. For example, if a database transaction is half-completed, capturing a snapshot at that moment means the state of the database reflects some changes while omitting others.

In contrast, during regular system maintenance, data migrations, or when storage space is limited, the implications of a crash consistent snapshot, while still relevant, might not be as critical, or alternatives for managing data consistency may be more readily available. Therefore, taking a snapshot during active and online applications introduces the highest risk of inconsistency and potential data integrity issues.