Documents can be stored at the post office, as illustrated in Post Office Directory
in GroupWise 8 Troubleshooting 3: Message Flow and Directory Structure. This is the simplest configuration, but it is not recommended for libraries where substantial growth is anticipated because documents stored at the post office cannot easily be moved to a different location where additional storage space is available.
Preferably, documents should be stored outside the post office, in document storage areas. Document storage areas are physical locations, such as drive volumes, optical devices, hard drives on other servers, and so on. Document storage areas can be located anywhere that the POA can access them locally or using direct network access (mapped drive or mounted file system).
A document storage area has the same internal directory structure that is used to store documents at the post office. The only difference is that a document storage area can be located anywhere in your system. Therefore, a document storage area can be moved easily, so it is easy to expand your document storage capacity if you store documents in a document storage area rather than at the post office.
For complete information on document storage areas, see Section 22.6.2, Managing Document Storage Areas.