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Borg Backup (replacing rdiff-backup)

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Over the past n years, I've used rdiff-backup as my backup solution. However, this has grown increasingly irritating because :

  • If a backup gets terminated early, 'reverting' the incomplete backup takes a long time
  • Backups would always complain about bad access modes (MSDOS backup disk vs Linux host system?)
  • My backup scripts were written in Perl, which is feeling/looking like a weakness now
  • My backup scripts were due for an overhaul anyway, since new disks/repos have appeared, and old machines have been retired.

Checking online shows that a number of new solutions have appeared, and so I decided to test one out (and actually switch if successful).

The key requirements were :

  • Backups should be incremental
  • Backup media should be encrypted (so that I can rotate two sets of media, and store one 'insecurely' off-site without worrying)
  • Decent include/exclude mechanism for files/folders
  • Ability to back up accross network
  • Simple tools to get access to my data in the future (or a disaster scenario)
  • Support in main-line Fedora

Fortunately, borgbackup met all these criteria.

Single package required

NB: All the below needs to be done as root, so that all paths are traversible, and all permissions are preserved

dnf install borgbackup

Mount the media

It makes sense to create a consistent mount-point for the media, since that simplifies all the subsequent scripts :

mkdir -p /media/disk
mount /dev/sdd1 /media/disk

Initialise the repo

First time only (and this will require inventing a decently strong password, with which a keyfile stored with the repo will be secured) :

touch /media/disk/.mounted # enables media presence to be checked easily

borg init --encryption=repokey /media/disk/borg-home

Basic approach using Python

Check that the media is there :

import os

# Need to make sure backup drive is mounted...
disk = '/media/disk'

if not os.path.isfile( os.path.join( disk, '.mounted')):
  print("Error : Need to mount %s" % (disk,))
  exit(1)

export the password locally

This gets printed out, so it can be executed on the command line easily:

repo = os.path.join( disk, 'borg-home')

print('')
print("""export BORG_PASSPHRASE=`zenity --title 'Borg Password' --entry --hide-text --text 'Please enter Borg password'`""")
print('')

And produce the command-line text

Creating the necessary command-line entries is easier, and more maintainable, in Python :

def beautify(comment, cmd):
  cmd= ' '.join([ l.strip() for l in cmd.split('\n') if not l.strip().startswith('#') ]).strip()
  cmd = cmd.replace('{repo}', repo)
  return "echo \"%s\" && \\\n  %s" % (comment, cmd)

if True:
  cmd="""
  borg create
    --progress
#   --list --dry-run
    --exclude '*/.Trash*/'
    --exclude '*/checkpoint*/'
    {repo}::'rdai-{now}'
    /mnt/rdai
  """
  print(beautify("RedDragonAI", cmd))

Include some utility commands too

print(beautify("See the archives", "borg list {repo}"))
print(beautify("See the compression", "borg info {repo}"))

Check that the backup can be restored

THIS IS A VERY IMPORTANT STEP FOR ANY BACKUP SOLUTION!

Quick example with a file that I knew should be in a specific backup batch :

mkdir -p ~/tmp/
cd ~/tmp/
borg extract  /media/disk/borg-home::personal-2019-01-09T01:03:27 mnt/data/Personal/Property/StreetEasy.txt

All done.

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