Snapshot Frequency

If trending is enabled, the reporting module will make a snapshot copy of the database once every hour. Use the sample-collection command to set how many minutes past the hour this occurs.

If trending is not enabled and snapshot reports are, this snapshot copy will be made according to the schedule you have set using the snapshots schedule command.

If both trending and snapshot reports are enabled, the snapshot reports will be generated according the schedule you set with the snapshots schedule command, using the hourly database copy.

Lastly, if neither trending nor snapshot reports are enabled, then the snapshot copy of the database will not be made.

All prefixes are trended live at 30 second intervals. The total number of prefixes is limited by the smaller of two factors:

• the trending prefix-limit command allows you to set a limit (default is 100)
• the system imposes a limit of 100 if you have more than four configured links; otherwise, its limit is 500

If the limit is reached, then the prefixes that will be trended is based on the following (in the order of preference):

• prefixes listed in trend-live report group
• prefixes listed in other report groups
• prefixes listed in decision policy groups
• “Top” prefixes based on decreasing measurement rate (this top prefix list is refreshed every 24 hours)

Snapshots are enabled by default; trending is disabled by default. See the snapshots on and trending on commands.

Use the delete report and clear trending commands to manage the amount of hard disk space required for snapshot reports and the trending database.