The Time Selector is displayed in the top-left corner of the navigation bar and controls the global time interval for metrics displayed in the ExtraHop Web UI. Navigating from one area to another will not change the time interval for the metrics you are viewing. Whether you are viewing metrics in a dashboard, or drilling-down to view detailed metrics, the time interval stays the same.
Here are some considerations about time intervals:
- Time intervals are preserved for each login session. Logging out of the Discover appliance will reset the global time interval to the last 30 minutes. You can access the five most recent unique time intervals from the History tab of the Time Selector.
- The time interval is included at the end of the URL in your browser. To share a link with others that maintains a specific time interval, copy the entire URL. To maintain a specific time interval after logging out of the Discover appliance, bookmark the URL.
- The time interval associated with the collection and presentation of network data is determined by your local NTP server by default. You can change the system time in the ExtraHop system from the Admin UI. For more information, see Configure the system time in the Admin UI Guide.
- Click the time interval in the upper left corner of the page (for example Last 30 minutes).
Select from the following interval options:
- A preset time interval (such as Last 30 minutes, Last 6 hours, Last day, or Last week).
- A custom unit of time.
- A custom time range. Click a day to specify the start date for the range. One click will specify a single day. Clicking another day will specify the end date for the range.
- Compare metric deltas from two different time intervals.
- Click Save.
|Tip:||You can also set the time interval from the History tab by selecting from up to five recent time intervals set in a previous login session.|
On a dashboard page, metric data is reloaded automatically. For time intervals such as the last 30 minutes, day, or week, dashboards continuously update to display the latest data for that time interval.
On a protocol page, detail metrics page, or records query page, metric data are reloaded on request. On these pages, the time interval includes a blue refresh icon and gray text that indicates when the metric or record query was last loaded. To reload the metrics or query for the specified time interval, click the refresh icon.
The ExtraHop system stores metrics in 30-second buckets of time. Metric data are then aggregated or rolled up into additional five-minute and one-hour buckets. Aggregating data helps to limit the number of data points rendered on a time-series chart so the granularity of data is easier to interpret. The time interval you select determines the best aggregation, or roll up, of data to display in a chart for the period of time you are viewing.
For example, if you select a large time interval, such as one week, metric data is aggregated into one-hour roll ups. On the x-axis of a line chart, you see a data point for every hour instead of a data point for every 30 seconds. If you want to increase the level of granularity, you can zoom in on a chart or change the time interval.
The ExtraHop system includes built-in high-precision metrics with 1-second roll ups, which are the Network Bytes and Network Packets metrics. These metrics are associated with a device or network capture source. For more information on how to view these metrics in a chart, see Display the maximum rate in a chart.
The ExtraHop system also includes built-in metrics for identifying the single busiest millisecond of traffic within a 1-second roll up. These metrics, which are Maximum Network Bytes per Millisecond and Maximum Packets per Millisecond, are associated with a network capture source and help you detect microbursts. Microbursts are rapid bursts of traffic that occur within milliseconds.
The following table provides information about how data is aggregated based on time interval.
|Time Interval||Aggregation Roll Up (if available)||Notes|
|Less than six minutes||1-second||A 1-second roll up is only available for custom metrics and for the following
|120 minutes or less||30-second||If a 30-second roll up is not available, a 5-minute or 60-minute roll up displays.|
|Between 121 minutes and 24 hours||5-minute||If 5-minute roll up is not available, a 60-minute roll up displays.|
|Greater than 24 hours||60-minute||–|
|Note:||If you have an extended datastore that is configured for 24-hour metrics, a specified time interval of 30 days or longer displays a 24-hour aggregation roll up.|