News Server Operation - Spools

Spools

When the server stores the body of an article, it places it in a disk storage area generically called a "spool". There are several common ways in which the spool may be organized:

• One file per article is the oldest storage scheme, still in common use on smaller servers and replicated in many clients. Its performance capability is a direct function of the underlying operating system's ability to create, remove and locate files within a directory, and often this scheme is insufficient to keep up with modern Usenet traffic. It does, however, allow for the greatest flexibility in managing the amount and location of storage used by the server. Nearly all current software using this scheme stores articles using the B News 2.10 layout.

• Cyclical storage has been in increasingly common use since the 1990s. In this storage method, articles are appended serially to large indexed container files. When the end of the file is reached, new articles are written at the beginning of the file, overwriting the oldest entries. On some servers, this overwriting is not performed, but instead new container files are created as older ones are deleted. The major advantages of this system include predictable storage requirements if an overwriting scheme is employed, and some freedom from dependency on the underlying performance of the operating system. There is, however, less flexibility to retain articles by age rather than space used, and traditional text manipulation tools such as grep are less well suited to analyzing these files. Some degree of article longevity control can be exercised by directing subsets of the newsgroups to specific sets of container files.

• In some cases, a relational database or similar is used to contain the spool. This is most commonly seen with Internet forum software that also offers an NNTP interface.

• Some servers, such as INN, allow multiple storage schemes to be used at once. Various hybrid storage schemes have also been used in news servers, including different organizations of the file-per-article method, or smaller containers carrying perhaps 100 articles apiece.