You can backfill metrics by running the same command and supplying an additional --timestamp argument. The timestamp argument accepts an ISO 8601 date and time stamp in UTC time for example: 2017-01-01T12:00:00.000Z
Keep in mind that CloudWatch will only retain your metrics for a certain period, decided by the granularity of your metrics. The retention period is:
- Data points with a period of 60 seconds (1 minute) are available for 15 days
- Data points with a period of 300 seconds (5 minute) are available for 63 days
- Data points with a period of 3600 seconds (1 hour) are available for 455 days (15 months)
While you can send metrics with millisecond precision, the minimum value CloudWatch will store is at the 1 minute level. Anything ...
