Daylight saving time and blackout periods

Blackout periods for synthetic transaction monitoring are used to disable monitoring and notifications, such as for maintenance or troubleshooting. In Execution Plans, you can set blackout periods to occur regularly, on a weekly schedule, or you can set blackout periods to occur once.

Many countries and regions employ daylight saving time (DST), also called summer time, which is the practice of advancing clocks in spring to add more daylight hours in the evening. In autumn, clocks are adjusted back an hour, to return to the region's standard time. Changes to DST can affect the time of the blackout period, so that the start time of a blackout period for an Execution Plan can vary one hour when the clocks are adjusted. This discrepancy is because blackout periods are set based on UTC time.

For example, if you set the blackout period to start at 23:00 in your local time, and to end four hours later, the system translates the end time to 03:00. After the change to DST, the blackout occurs at midnight in your local time and ends four hours later at 4:00.

The End Time displayed by the system, as shown in the following image, is calculated using the selected Start Time and Duration:

Blackout settings for synthetic monitoring

Note

The times and dates begin and end according to the local time set on the TrueSight console. That is, you set the time in the console, and the equivalent time is set for associated TEA Agents.

For example, if the console is set to Central Standard Time and you set the blackout period to start at 23:00, in Eastern Standard Time it will start at 00:00 (midnight).

The following tables present a blackout period over several time zones.

Click here to see a list of time zone abreviations used in the following examples.

The following time zones are represented:

City	Standard time, UTC offset	Daylight saving time, UTC offset
Chicago	Central Standard Time (CST), UTC-6	Central Daylight Time (CDT), UTC-5
Atlanta	Eastern Standard Time (EST), UTC-5	Eastern Daylight Time (EDT), UTC-4
Madrid	Central European Time (CET), UTC+1	Central European Summer Time (CEST), UTC+2
London	Greenwich Mean Time (GMT), UTC 0	British Summer Time (BST), UTC+1

No change. The following table shows the blackout period (with a blue background) when no DST change takes place. The blackout period starts at 23:00 and ends four hours later, at 03:00.

	Time zone
	TrueSight console time CST (UTC -6)	Agent 1 EST (UTC-5)	Agent 2 CET (UTC+1)	Agent 3 GMT (UTC 0)
	22:00	23:00	05:00	04:00
Start time	23:00	00:00	06:00	05:00
	00:00	01:00	07:00	06:00
	01:00	02:00	08:00	07:00
	02:00	03:00	09:00	08:00
End time	03:00	04:00	10:00	09:00
	04:00	05:00	11:00	10:00

Spring change to DST. The following table shows the blackout period (with a blue background) when clocks are advanced from 01:59 to 03:00 on the console time zone. The blackout period starts at 23:00 and ends at 04:00, a difference of four hours on the console time zone.

Note

The assumption is that the time changes are taking effect at the agent locations as well.

	Time zone
	TrueSight console time CST to CDT (UTC -5)	Agent 1 EST to EDT (UTC-4)	Agent 2 CET to CEST (UTC+2)	Agent 3 GMT to BST (UTC+1)
	22:00	23:00	05:00	04:00
Start time	23:00	00:00	06:00	05:00
	00:00	01:00	07:00	06:00
	01:00	03:00*	08:00	07:00
	03:00*	04:00	09:00	08:00
End time	04:00	05:00	10:00	09:00
	05:00	06:00	11:00	10:00

^{* Change in daylight saving time}

Autumn change off of DST. The following table shows the blackout period (with a blue background) when clocks are adjusted from 01:59 to 01:00 on the console time zone. The blackout period starts at 23:00 and ends at 02:00, a difference of four hours on the console time zone.

Note

The assumption is that the time changes are taking effect at the agent locations as well.

	Time zone
	TrueSight console time CDT to CST (UTC -6)	Agent 1 EDT to EST (UTC-5)	Agent 2 CEST to CET (UTC+1)	Agent 3 BST to GMT (UTC 0)
	22:00	23:00	05:00	04:00
Start time	23:00	00:00	06:00	05:00
	00:00	01:00	07:00	06:00
	01:00	01:00*	08:00	07:00
	01:00*	02:00	09:00	08:00
End time	02:00	03:00	10:00	09:00
	03:00	04:00	11:00	10:00

^{* Change in daylight saving time}

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