N-central Help

Set the time-to-stale and default scan intervals

Set the time when the most recent service data becomes stale if no new data has not been received. Also set the default scan interval, the time between each scan of the service.

When monitoring a device, the agent or probe scans the service after the specified scan interval and sends data to the central server. If the Time-to-Stale (TTS) value elapses before the agent or probe sends any new data, the state of the service changes to Stale. However, a high volume of network traffic can cause a delay in sending data to the central server. If the specified TTS value is too close to the scan interval value, the service can constantly be in the Stale state. To avoid this, ensure the TTS is at least twice the scan interval. The Event Log service does not require a TTS value; it receives events as they occur.

During an upgrade of the central server, if the default values of the time-to-stale and scan intervals have been changed, you need to specify their settings again after the upgrade.

This feature is only available at the system or product administrator level.

  1. On the Administrator Console in the Services area, click Time-to-Stale and Default Scan Intervals.
  2. In the Time-To-Stale column, enter the amount of time before the service changes to a stale state if new data has not been received.
  3. In the Default Scan Interval column, enter the time, in minutes, between each scan in integer or cron string format.

    A cron string consists of five fields with each field separated by a space and represented by an asterisk. For information on the cron format, see http://www.nncron.ru/help/EN/working/cron-format.htm. The table below provides some examples of cron strings.

    Cron String Examples

    Description

    0 4 * * *

    Scans at 4:00 a.m. every day of the month, every month, and every day of the week.

    0 22 * * *

    Scans at 22:00 p.m. every day of the month, every month, and every day of the week.

    */5 * * * *

    Scans every five minutes, every hour, every day of the month, every month, and every day of the week.

    */59 4 * * *

    Scans at 4:00 a.m. and 4:59 a.m., every day of the month, every month, and every day of the week.

  4. For each service, select Propagate only if you would like to apply any changes to the settings to all of the devices that are running this service. Otherwise, the changes are applied only to the new devices.

    The Interval Type column indicates the type of value that can be entered for the scan interval.

  5. Click OK.

The default time-to-stale and the scan intervals are set and, if selected, propagated to any existing service.