SiteScope User's Guide

CPU Utilization Monitor

The SiteScope CPU Utilization Monitor reports the percentage of CPU time that's currently being used on the server. It's important to watch CPU usage on your Web server to ensure that it doesn't become overloaded on a regular basis.

Each time the CPU Utilization Monitor runs, it returns a status message and writes it in a log file.

Usage Guidelines

Why should I use this monitor?

When CPU usage becomes too high, visitors to your site will either find it very slow, or if your web server hangs as a result of the high usage, they simply won't be able to access it. Therefore, it's very important to keep an eye your CPU usage and do something about high usage before it causes you problems.

What should I monitor?

Whether you're running a machine with a single CPU or one with multiple CPUs, you only need to create one CPU monitor. If you have multiple CPUs, SiteScope will report on the average usage for all of them.

How should I schedule my monitors?

In general, the CPU Monitor doesn't need to be run as often as some of the other monitors. If you don't usually suffer from CPU problems, you can run it less frequently - perhaps every half hour or so. If you are prone to CPU usage problems, you should run it more frequently. All machines will have short spikes of CPU usage, but the primary thing that you're looking for is high usage on a regular basis. This indicates that your system is overloaded and that you need to look for a cause.

Status

The Status reading is the current value returned by this monitor; for example, 68% used. SiteScope displays an average for multiple CPU systems. On NT, this is the average CPU usage between runs of the monitor. On Unix, this is the instantaneous CPU when the monitor runs.

The status is logged as either OK or warning. A warning status is returned if the CPU is in use more than 90% of the time.

Completing the CPU Utilization Monitor Form

To display the CPU Utilization Monitor form, either click the Edit link for an existing CPU Utilization Monitor in a monitor table, or click the " Add a new Monitor to this group" link on a group's detail page and choose the " Add CPU Utilization Monitor" link.

Complete the items on the CPU Utilization Monitor form as follows. When all the items are complete, click the Add Monitor button.

Server: Choose the server that you want to monitor. The default is to monitor CPU usage on this server. Click the choose server link to monitor CPU usage on another server.
Update every: Enter how frequently the CPU's utilization should be monitored. The drop-down list to the right of the text box lets you specify time increments of seconds, minutes, hours, or days. You must specify a time increment of at least 15 seconds.
Title (Optional): Enter a name for this monitor. This name appears in the Name text box on the monitor table when you open the group's detail page. If you don't enter a name, a default name will be created.

Advanced Options

The advanced options give you the ability to customize error and warning thresholds. If you choose not to set them, SiteScope will use preset defaults if available. If a default is not available, SiteScope will not be able to utilize the condition.

Disable

Check this box to temporarily disable this monitor and any associated alerts. To enable the monitor again, clear the box.

Verify Error

Check this box if you want SiteScope to automatically run this monitor again if it detects an error. When an error is detected, the monitor will immediately be scheduled to run again once.

Note: In order to change the run frequency of this monitor when an error is detected, use the Update every (on errors) option below.

Note: The status returned by the Verify Error run of the monitor will replace the status of the originally scheduled run that detected an error. This may cause the loss of important performance data if the data from the verify run is different than the initial error status.

Warning: Use of this option across many monitor instances may result in significant monitoring delays in the case that multiple monitors are rescheduled to verify errors at the same time.

Update Every (on error)

This options allows you to set a new monitoring interval for monitors that have registered an error condition. For example, you may want SiteScope to monitor this item every 10 minutes normally, but as often as every 2 minutes if an error has been detected. Note that this increased scheduling will also affect the number of alerts generated by this monitor.

Schedule (Optional)

By default, SiteScope's monitors are enabled every day of the week. You may, however, schedule your monitors to run only on certain days or on a fixed schedule. Choose the Edit schedule link to create or edit a monitor schedule. For information about creating schedules, read these instructions.

Monitor Description (Optional)

Enter additional information about this monitor. The Monitor Description can include HTML tags such as the <BR> <HR>, and <B> tags to control display format and style. The description will appear on the Monitor Detail page.

Report Description (Optional)

Enter a description for this monitor that will make it easier to understand what this monitor does. The description will appear on Management Reports and on the info pop-up for a monitor.

Depends On (Optional)

To make the running of this monitor dependent on the status of another monitor or monitor group, use the drop-down list to select the monitor or group on which this monitor is dependent. Select None to remove any dependency.

Depends Condition (Optional)

If you choose to make the running of this monitor dependent on the status of another monitor, choose the status condition that the other monitor or monitor group should have in order for the current monitor to run normally. The current monitor will be run normally as long as the monitor or group on which it depends reports the condition selected in this option.

List Order (Optional)

By default, new monitors are listed last on the Monitor Detail page. You may use this drop-down list to choose a different placement for this monitor.

Error if

By default, SiteScope only generates a warning status for the CPU monitor. You may choose to have SiteScope generate an error based on either the total CPU percentage or the percentage of CPU a particular CPU. Use the comparison value and comparison operator list to specify an error threshold such as: >= (greater than or equal to), != (not equal to), or < (less than).

Warning if

By default, SiteScope generates warnings whenever CPU usage goes over 90%, but you can change this to generate a warning based upon a different percentage or an actual amount of CPU in use. Complete this section just as you would for the Error if section, described above.

Good if

SiteScope reports a good status for CPU monitors. You may change this to a specific percentage if you prefer.