LimitDiskUsage

From RdiffBackupWiki

This scripts currently works only if the backup destination is local, but it should be easy to adapt this for remote backups by using ssh to call du remotely.

#!/bin/bash

# backup destination dir
backupdir=/mnt/backups/foo

# rdiff-backup binary
rdiffbackup=/usr/bin/rdiff-backup

# remove old increments from the backup as long as du reports
# more bytes used by the backup dir than the following limit
maxbytes=$((350 * 1024 * 1024 * 1024))

# but never delete increments younger than the following limit in seconds
keepseconds=$((7 * 60 * 60 * 24))

# gather the list of timestamps of all backup increments into an array
increments=($($rdiffbackup --list-increments --parsable-output $backupdir | while read a b; do echo $a; done))

# while we still have at least two increments,
# and we are allowed to delete the oldest increment,
# and du reports more disk usage than allowed,
# remove the oldest increment
while ((
  ${#increments[*]} > 1 &&
  $(date +%s) - ${increments[0]} > $keepseconds &&
  $(du --block-size=1 --summarize $backupdir | while read a b; do echo $a; done) > $maxbytes ))
do
  $rdiffbackup --remove-older-than $((${increments[0]} + 1)) $backupdir || exit
  unset increments[0]
  increments=(${increments[*]})
done