Will this custom backup retention setup [eventually] keep 5 backups?

I have this Custom backup retention:
(I also have it set up to backup every 3 days)

I am expecting / hoping it to keep 5 backups (restorable):

  • Keep one backup within the last week
  • Keep one backup within the last 3 weeks
  • Keep one backup within the last 6 months
  • Keep one backup within the last year
  • Keep one backup within the last 2 years

Is this correct?

You’ll end up with more than 5 backup versions.

If you are running backups every 3 days, then your retention rule will have this effect:

1W:1D – for the first week, keep at most 1 backup per day. Since you only back up every 3 days, you’ll have 2 or 3 backups retained by this rule.
3W:1W – for the most recent 3 weeks, retain only 1 backup per week. The earlier rule overrides this for the first week. For weeks 2 and 3 you will have 1 backup each.
6M:1M – for the most recent 6 months, keep 1 backup per month. Again, the earlier rules still apply so your first month will have more than just 1 backup. The second through sixth months will each have one backup retained.
1Y:6M – for the most recent year, keep one backup every 6 months. Again, the earlier rules cause this to not really have an effect until after 6 months pass. The rest of the year (6 month span) will have only one backup total.
2Y:1Y – for 2 years keep 1 backup a year. Earlier rules will cause more than 1 backup in the first year obviously. The second year will only have 1 backup version retained.

After 2 years all backup versions are deleted. So you’ll never be able to restore more than 2 years ago with this retention setting.

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Thank you @drwtsn32, I think I understand how the config relates to what (how many backup “copies”) are kept now.

For my updated config of: 3W:U,5M:1M,2Y:6M
Would the following explanation be correct?

For the most recent 3 weeks, retain all backups (up to 7 backups, as backups happen ~every 3 days; 3W = 21D, and 21/3 = 7 backups)
For the most recent 5 months, retain a monthly backup (up to 5 additional backups)
For the most recent 2 years, retain a backup for every 6 months (up to 4 additional backups)

Thanks for your help,

I think you meant to to say “5 months” here… But yeah you got it!

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