A user interface in a file-based networked storage server enables a user to selectively enable or disable an option to require read-after-write verification for sets of data stored by the file-based networked storage server. In response to a request from a client, specified data is written to a magnetic storage device managed by the file-based networked storage server. A determination is made of whether the specified data is associated with a set of data for which the option to require read-after-write verification is enabled, and if so, then the specified data written to the magnetic storage device is verified, prior to, and as a precondition of, acknowledging completion of the write to the client. The specified data written to the magnetic storage device is designated as being in a WORM state only after successful completion of said writing and said verifying.