Are you concerned about MWS not being able to handle amount of files? In reality MWS also stores files on a file system is so called Content Service (you can configure this file system location using Administration > Content > Content Services Admin). But even though files will be stored on a file system they will not be easily accessible from file system directly because MWS applies some logical structure on top, changes names of files etc.
As another option you can do your own implementation of IAttachmentsProvider interface which is meant to save/retrieve raw files and your implementation may quite well store files physically on file system or anywhere your want. Then use your implementation to configure Attachments Panel control
#webMethods#webMethods-BPMS#MWS-CAF-Task-Engine