pflogsumm.pl is designed to provide an over-view of postfix activity, with just enough detail to give the administrator a "heads up" for potential trouble spots. Reports includes: Total number of messages and bytes; Hosts/Domains; senders and Recipients; per-hour traffic reports; summaries of warnings, fatal errors, and panics; and so on ...
changetrack is a program to monitor changes to files. If files are modified one day, and the machine starts working incorrectly some days later, changetrack can provide information on which files were modified, and help locate the problem. Changetrack will also allow recovery of the files from any stage.
Osiris is a host integrity management system that can be used to monitor changes to a network of hosts over time and report those changes back to the administrator(s). Osiris takes periodic snapshots of the filesystem, configurations, and logs, and stores them on a central management host. When changes are detected, Osiris will log these events and optionally send email to an administrator. Osiris also has preliminary support for monitoring other system data, including user lists, file system details, kernel modules, and network interface configurations.
Performance Co-Pilot (PCP) is a framework and set of services for supporting system-level performance monitoring and performance management. It provides a unifying abstraction for all of the interesting performance data in a system, and allows client applications to easily retrieve and process any subset of that data using a single API. A client-server architecture allows multiple clients to monitor the same host, and a single client to monitor multiple hosts. Archive logging and replay are integrated so that a client application can use the same API to process real-time data from a host or historical data from an archive.
logsurfer is a log checking/auditing tool similar to swatch and logcheck but with the capability of handling multi-line messages and dynamically adapting the ruleset. It is written in portable C, well documented, fast, and flexible. It works on any textfile or stdin, can be run at intervals or continuously, and has timeouts and resource limits.
Log4j is a logging package written in Java. Log4j allows you to log to a file, a java.io.Writer, a remote server, or a syslog daemon. The package is designed so that log statements can remain in shipped code without incurring a high performance cost. One distinctive feature of log4j is the notion of hierarchical loggers. Using hierarchical loggers, it is possible to select (at runtime) which log statements are output at arbitrary granularity. Users can choose to implement their own log formats and output strategies.
Tailbeep opens a file (-f), seeks to the end, and watches for a string (-s). If the string is found, a beep is sent to the specified tty (-t) device. You can also daemonize (-d) it. It was written to watch /var/log/messages for the DENY string (to catch anyone trying to break into a firewall), but you can use it to watch any open file that gets appended to. You can also create a log if you like, so you can record the events, in long or short mode. Tailbeep requires write access to one of the tty devices on the console.