Volume Number: 17 (2001)
Issue Number: 05
Column Tag: KoolTools

PageSentry 3.0

by Ben Baumer

There are few servers on our network that we rely on more than our PageSentry machine. Whether we're here or not, PageSentry is in constant communication with all of our servers, being the electronic eyes that we simply don't have. How much more difficult would my life be if I didn't have PageSentry waking me up a 3 A.M. to tell me that the FileMaker server is down? Probably much more difficult. The latest version of Maxum Development's network monitoring champ marks a surprising improvement on what was already a dynamite program.

Like Men and Mice, Maxum must have gotten the message that remote administration is now a must, because PageSentry 3.0 has a built-in web server to provide you with just that ability. As an added bonus, the web server requires minimal setup. Simply launch the PageSentry application, fill out the information under the "web monitor" tab in the preferences menu, and connect to your PageSentry machine with a web browser.

If you happen to be running another web server on the machine that PageSentry is on, you can change the port on which PageSentry runs (the default is port 80). Setting up the Sentries and Notifiers is much like it is in previous versions of PageSentry, with a few small changes. First, PageSentry 3.0 adds a new method of organizing your Sentries, called "Groups." With Groups, you can use a series of Sentries in combination to give you a better picture of what went wrong with your server. For example, on a web server you might have a standard Ping Sentry and an HTTP Sentry. If they are part of the same group, and one Sentry fails, the other will be run immediately. That way, if you get a report that the HTTP Sentry failed, but the Ping Sentry is still OK, it is likely that your web server application has crashed, but the machine itself has not necessarily crashed. This could save you a trip to the office if you can fix the problem with Timbuktu.

The second major new feature of PageSentry 3.0 works in conjunction with a background application called ProcWatch. Install ProcWatch on a remote server, and PageSentry will be able to check a machine for an individual process. To recall the previous web server example, this could tell you definitively whether the web server application had crashed. When using ProcWatch, be mindful of memory concerns, as ProcWatch takes up almost one megabyte of memory on the host computer. Clearly, this feature has great implications for checking up on servers that don't already have a convenient type of Sentry, or on secure servers that don't have a TCP/IP connection.

Finally, let's take a look at the PageSentry web interface.

We can see already that this window gives us much more information that the normal PageSentry status window, not to mention the fact that it can be accessed from anywhere in the world. Perhaps the coolest addition is the "Up Time Percentage" column, which seems fairly self-explanatory. Note that this percentage goes to three decimal places, and that you can reset all Sentries in the PageSentry application itself. Once you've had your PageSentry application running continuously for a couple of weeks, you will start to get some really meaningful information from the "Up Time Percentage." After gathering statistics for almost a month, all but one of our servers are in the 98.5-100% range. These are essentially stable machines that may have had the occasional failure. However, one machine is consistently in the 97% range, and it is now no secret that the thing is relatively unstable. We have PageSentry to thank for that information.

Current users of PageSentry will jump at the chance to upgrade to version 3.0, which brings several insightful and useful new features to a program that can already be the nervous system of your network. The new web-based administration will increase your ability to keep tabs on your network, both in its ability to report statistics, as well as create new Sentries or modify old ones from a remote location. But perhaps the greatest improvement comes with ProcWatch, which will increase the number and type of servers that PageSentry can accurately monitor, thereby making it far more powerful and useful. This is a worthwhile upgrade.