External storage areas do not store content. Instead, external stores point to the actual storage area, which can be a CD-ROM, a file system, a URL, or a user-defined store.
Data in an external store is not physically managed by Content Server. There are significant limitations on content in an external store. For example, you cannot index content or the properties of content in an external store.
External stores require a plug-in that you must create before you create an external store. The plug-in can run on the server side or client side, although a client-side plug-in could provide better performance. Documentum provides code for sample plug-ins in the DM_HOME/unsupported/plugins directory.
There are three types of external stores:
External file store
Use external file stores for legacy files in external file systems, optical disks, and CD-ROM files.
External free store
External free store storage areas allow users to specify a token that is not a file path or a URL. An external free store enables you to define your own token standard and means of retrieving the content associated with the token. Write your own content retrieval mechanism through a DLL plug-in, which is described by a plug-in object.
You can also use the external free store pages to manually create XML stores. Use XML stores to store and query large volumes of XML content. An XML store is a native XML database that is fully optimized for XML content.
External URL store
External URL stores provide support for token-mode operation where the token is a URL. The tokens specified in the Setpath operation must follow the URL standard. The client and the server do not validate the format of the URL.
For information about creating, viewing, or modifying external stores, refer to Creating, viewing, or modifying external stores.
The Documentum XML Store Installation and Administration Guide provides more information about external XML file stores.