File Synchronization

With bandwidth at a premium over WAN links, and enterprises maintaining large code bases and documentation sets, it doesn't make sense to copy every updated file over the WAN. File replication, which is part of the file-synchronization process, is a better option because it uses less bandwidth.

No Smoke and Mirrors

In its simplest form, synchronization resembles file copying. But synchronization is more complex, and can handle several people changing source files at the same time. In this case, the software typically mirrors the changes to machines around the office or across the WAN. Synchronization software recognizes file conflicts. To prevent the data loss inherent in simple file replacement, the synchronization software lets the systems administrator preconfigure the appropriate rules or notifies the administrator before replication occurs.

A similar problem occurs in the database world, where multiple users try to update a data row at the same time. Say, for instance, two salespeople are simultaneously changing a large customer's order. One adds a few more widgets, while the other adds twice as many. The database administrator must implement file locking to prevent data corruption. The parameters specify which sales order is valid so that incorrect information is not accepted--or replicated. This means complex rules.

Not so with file synchronization. There, the software notifies the administrator when conflicting versions of the information appear or when users are introducing nearly duplicate entries into the directory. In most cases, the administrator must arbitrate the conflict manually.