Introduction

In administering Linux Servers for an Internet Services Provider it has become necessary for configuration files to be modified by multiple users and scripts. This raises several serious issues that need to be address to ensure the integrity of the system.

1.

Concurrent Access. Some mediation is required to ensure that all simultaneous edits to files are accepted.

2.

Roll Back. A mechanism is required such that either user or script errors can readily be reversed.

3.

Audit Trail. Edits need to be traceable to a user or script in order to prevent the recurrence of problems that may occur from time to time.

Roll back and audit trails are essentially version management issues and a system such as The Revision Control System, RCS or Source Code Control System, SCCS can be employed. Systems such as RCS and SCCS do not, however, provide for concurrent access. Concurrent Versions System, CVS is a revision control system, built on RCS that allows files to be checked out concurrently by multiple users. CVS manages edits of the same file by multiple users transparently unless the same part of the same file is edited in which case manual conflict resolution is required. As management of concurrent access is a key issue that needs to be addressed CVS was chosen as the basis of the system as it provides all three attributes that we require.