Request for smart retention of quarterly and annual backups

Smart retention works for days, weeks, and months. I would like to request that it also support specifying quarters and years, please. This is the policy I would like to be able to specify:

1 daily for last week (1-7 days from today backwards in time)
1 weekly for last month (2, 3, 4 weeks back)
1 monthly for last quarter (2, 3 months back)
1 quarterly for last year (2, 3, 4 quarters back, i.e. 6, 9, 12 months back)
1 annual all the way till the first backup (2-n years back)

Specifying years with ‘Y’ is already supported.

I made a short overview of the options here:

As for quarters, I could see it being used, but it seems a bit superfluous… that’s just my opinion.

I agree, too. Adding a part like 1Y:3M can give the desired behavior.

Just out of curiosity, is a “quarter” pretty much as standardized as Day, Week, Month, and Year?

When I hear it in the US I figure the following (unless it’s a FISCAL quarter):

  • Q1 = Jan-Mar
  • Q2 = Apr-Jun
  • Q3 = Jul-Sep
  • Q4 = Oct-Dec

I actually assumed it would just be any arbitrary quarter of a year, i.e. 3 months. I guess that’s two interpretations.


  1. Regarding quarters:
    I meant going backwards from the current date, and keeping the backups from “6, 9, and 12 months back”. “Quarterly” was thus the incorrect term. “3-monthly” would be more accurate.

Generically speaking, I would like the ability to specify that I keep only every n-th backup of each time interval (e.g. every 3rd monthly backup, every other weekly backup, etc.), and delete the others in that interval (delete monthly backup numbers 1, 2, 4, 5, 7, etc. going backwards in time).

  1. Regarding justification:
  • The presumption is that the longer you haven’t needed something, the less likely it is that you will need it. Since we want to minimize the number of backups we retain while still providing coverage to fall back upon, the math makes sense. It permits for a more gradual staggering of deletions. 4 weeks in a month, 3 months in a quarter, etc. You’re not suddenly reducing your coverage by 90% as you would if you kept 1 monthly vs. 1 annual backup.

  • I didn’t come up with this idea myself. The IT department at the Fortune 1000 company I was working was using this retention policy for their SQL database backups. The title of the guy I automated this for was “Senior Storage Administrator”. So someone who knew enough about data backups for a $2B/year company to feed his family in the Bay Area thought this was the way to go.

They kept daily backups for 1 month, weekly backups for 3 months, monthly backups for 36 months, quarterly backups for 60 months, and yearly backups for 85 months.

I want to be able to do the same with my backups.

  1. Regarding the existing featureset
    Even after reading the syntax description, I do not understand the current featureset. For all I know, there is a way (“1Y:3M”??) to accomplish what I am seeking. But I wasn’t able to determine that from the 1 paragraph of documentation.

But but keeping quarterly backups for 60 months is the same as keeping one backup per 3 months for 60 months 60M:3M.

The quarter semantics seem to complicate it further.