Using the Event Monitoring Service (June 2007)

Defining a Monitoring Request
Setting the Polling Interval
Chapter 2 31
Setting the Polling Interval
The polling interval specifies how often the resource monitor checks the
resource value. The polling interval is the maximum amount of elapsed
time before a monitor knows about a change in status for a particular
resource.
The shorter the polling interval, the more likely you are to have recent
data. However, depending on the monitor, a short polling interval may
use too much CPU and system resources. You need to weigh the
advantages and disadvantages between being able to quickly respond to
events and maintaining good system performance. Some considerations
are listed below. You may want to set:
• A minimum polling interval (10 seconds or 30 seconds) depending on
the monitor’s ability to process quickly. For most resource monitors,
the minimum is 30 seconds. Disk monitor requests can be as short as
10 seconds.
• A short polling interval (30 seconds or less) when it is critical that
you make a quick failover decision. MC/ServiceGuard monitors
resources every few seconds.
• A polling interval of 5 minutes or so for monitoring less critical
resources.
• A very long polling interval (4 hours) to monitor failed disks that are
not essential to the system, but which should be replaced in the next
few days.
Asynchronous monitors are event-driven, not polled. They generate
messages as events occur. Therefore, if the resource is an asynchronous
monitor, the Polling Interval field displays n/a.
To set the Polling Interval:
1. Specify the quantity of time in the numbered field.
2. Select the unit of time from the unit of measure field list (seconds,
minutes, hours, day). The maximum value is one (1) day.