Currently, raw data is kept for 35days, 10minute rollups are kept for 40days and 2hour rollups are kept for 3months.
within the next 30days, the retentions will be changing to:
<1minute resolution data kept for 8days
1minute to 10minute: resolution data kept for 15days
10minute to 1hour resolution data kept for 35days
1hour resolution data kept for 120days
with each higher resolution datapoint rolled up into each of the lower resolution windows. So a check that is running every 10seconds will have 10s resolution data for 8days, 1minute rollups kept for 15days, 10minute rollups kept for 35days and 1hour rollups kept for 120days.