Performance Alerts
Overview
Response time performance, not just availability, is vital for mission-critical sites and applications. The Performance Alerts feature allows the user to receive notifications when devices are not responding within configured thresholds. It is not tied to availability and uptime, but to response time metrics. Knowledge of how to configure devices in the AlertSite console is a prerequisite for using this guide.
Features
There are two measurement styles,
dynamic or
static.
- Dynamic thresholds compare the current response time to the average response time over a specified time period (10 minutes to 24 hours) as a percentage of the average over the past number of days (1 day to 7 days).
- Static thresholds compare the current response time to the average response time over a particular time period (10 minutes to 24 hours).
The number of monitoring locations is taken into account, either as a specific number or percentage. How to configure each feature is described below.
Configuration Options
From the Configuration dropdown in the Control Menu, choose Sites or Transactions, then select the device in you wish to configure Performance Alerts. The Performance Alerts configuration screen is accessed through the leftmost button in the upper right of the the Manage Site or Manage Transaction configuration screen:
The Performance Alerts configuration screen is presented as follows:
Enable/Disable Performance Alert Processing
This field is disabled by default. Select
Enable from the drop-down menu under
Enable/Disable Performance Alert processing, otherwise the notifications will not be sent.
Select Measurements for Averaging
This section is displayed only if the device has the Fullpage option enabled to gather metrics for each object on the page. This field gives you the ability to select
Fullpage or
Base page when averaging response time measurements.
Configure Performance Alert Thresholds
There are two methods for configuring thresholds: Dynamic or Static.
Dynamic
If selecting the Dynamic radio button, choose the time period (from 10 minutes to 24 hours) in which to compare the current response time to the response time average, based on the percentage, over the last 1 to 7 days.
For example, say the Dynamic section is configured as follows:
- Current response time average for the last 1 hour is equal to or greater than
- 60% for error
- 40% for warning
- Over the historical average response time during the last 1 day
- Detected from 1 monitoring location.
Say the average response time over the past hour is
12 seconds, and over the last day, the average response time was
10 seconds. No Performance Alert notification would be sent because the 2-second difference is only
20%, which is lower than either the warning (40%) or error (60%) thresholds.
Now, say the web site's response time increased significantly for unknown reasons. The site isn't down, but response time averaged
14 seconds over the last hour. The additional 4 seconds is
40% over the average during the previous 24 hours; this would trigger a warning alert. If the response time for the last hour increased to an average of
16 seconds, that 6-second increase would equal
60% and trigger a performance error alert.
Note that if the increase in response time was only being detected at 1 location and the threshold was configured to require 2 locations to detect the increase in response time, no alert would be sent.
Static
Static is more straightforward. Say the Static section is configured as follows:
- Current response time average for the last 1 hour is equal to or greater than
- 16 seconds for error
- 14 seconds for warning
- Detected from 50% of the monitoring locations (assume for this example that the site has 6 monitoring locations).
Say the response time over the last hour is
11 seconds. No warning (14 seconds) or error (16 seconds) threshold was reached. If
1 location reported an average of
14 seconds over the last hour, no warning alert would be sent. If
3 or more locations reported an average of
14 seconds over the last hour, a warning alert would be sent. If the average over the last hour was
16 seconds or longer from
3 or more locations, it would trigger an error alert.
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Configure Notifier
In order to receive Performance Alert notification, a
notifier must be configured to receive the alerts. You can modify an existing notifier or create a new one for the purpose.
NOTE: It is recommended to use
E-Mail or
Text Message for Performance Alerts since they are low-level warnings about web site performance, not an indication that your site is down. You may not want to be awakened in the middle of the night for a performance alert.
Bring up the
Configure Notifiers screen by clicking on
Notifiers in the Control Menu. To create a new notifier, click the
Add Notifier button in the upper right of the console.
In the
Configure Notifier Type/Description section:
- enter a Description
- leave Send a(n) as E-mail or select E-mail to wireless device (cell phone, pager, Blackberry, etc.)
- enter an email address in the To field.
If this is going to be a Performance Alert-specific notifier, deselect the check box labeled __Enable availability notifications in the
Configure Standard (Availability) Notifications section.
Under the
Configure Performance Alerts section
- check the box labeled Enable performance alerts
- select errors only or warnings and errors from the Select performance alerts of type drop down
- check the Repeat successive performance alerts box if you want to continue to receive Performance Alerts, otherwise leave it blank
To configure an existing notifier, click on the notifier in the
Notification Method column, then complete the
Configure Performance Alerts section as described above.
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