Linux – How to keep: daily backups for a week, weekly for a month, monthly for a year, and yearly after that

backupbashlinux

I need to backup data and config files on this server, daily. I need to keep:

  • daily backups for a week
  • weekly backups for a month
  • monthly backups for a year
  • yearly backups after that

All of this accomplished via a shell script run daily from cron.

This is how the backup files should look after 10 years of running:

blog-20050103.tar.bz2
blog-20060102.tar.bz2
blog-20070101.tar.bz2
blog-20080107.tar.bz2
blog-20090105.tar.bz2
blog-20100104.tar.bz2
blog-20110103.tar.bz2
blog-20120102.tar.bz2
blog-20130107.tar.bz2
blog-20130902.tar.bz2
blog-20131007.tar.bz2
blog-20131104.tar.bz2
blog-20131202.tar.bz2
blog-20140106.tar.bz2
blog-20140203.tar.bz2
blog-20140303.tar.bz2
blog-20140407.tar.bz2
blog-20140505.tar.bz2
blog-20140602.tar.bz2
blog-20140707.tar.bz2
blog-20140728.tar.bz2
blog-20140804.tar.bz2
blog-20140811.tar.bz2
blog-20140816.tar.bz2
blog-20140817.tar.bz2
blog-20140818.tar.bz2
blog-20140819.tar.bz2
blog-20140820.tar.bz2
blog-20140821.tar.bz2
blog-20140822.tar.bz2

Best Answer

You are seriously over-engineering this. Badly.

Here's some pseudocode:

  • Every day:
    • make a backup, put into daily directory
    • remove everything but the last 7 daily backups
  • Every week:
    • make a backup, put into weekly directory
    • remove everything but the last 5 weekly backups
  • Every month:
    • make a backup, put into monthly directory
    • remove everything but the last 12 monthly backups
  • Every year:
    • make a backup, put into yearly directory

The amount of logic you have to implement is about the same, eh? KISS.

This looks easier:

s3cmd ls s3://backup-bucket/daily/ | \
    awk '$1 < "'$(date +%F -d '1 week ago')'" {print $4;}' | \
    xargs --no-run-if-empty s3cmd del

Or, by file count instead of age:

s3cmd ls s3://backup-bucket/daily/ | \
    awk '$1 != "DIR"' | \
    sort -r | \
    awk 'NR > 7 {print $4;}' | \
    xargs --no-run-if-empty s3cmd del
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