Maybe. RDBMS should be able to recover from any crash consistent copy of storage, where crash consistency means the storage represents a state of the system at

Maybe. RDBMS should be able to recover from any crash consistent copy of storage, where crash consistency means the storage represents a state of the system at run time. FS snapshots provide this property for single volumes. The problem is that production RDBMS tend to span multiple volumes, e.g., for logs vs. data to pick a simple case. FS snapshots in this case may not be consistent which would cause recovery to fail. AFAIK this is why even robust RDBMS like MS SQL server use mechanisms like VSS to ensure data are flushed, which guarantees not just crash consistency but application consistency.