I'm trying to setup an automated backup system to backup my Raspberry Pi's data to my Mac Mini. However, calling neither borg init nor borg create from the RPi to the remote Mac Mini repo host seems to reach the borg server running on the Mac Mini. On the Mac Mini:

% sudo borg serve --debug --restrict-to-path /Users/borg/BorgRepos/RetroPie
$LOG DEBUG borg.logger Remote: using builtin fallback logging configuration
$LOG DEBUG borg.archiver Remote: 33 self tests completed in 0.12 seconds

On the RPi:

$ sudo borg create --debug --stats borg@octolen:/Users/borg/BorgRepos/RetroPie2::Friday2 RetroPie
using builtin fallback logging configuration
35 self tests completed in 0.59 seconds
SSH command line: ['ssh', 'borg@octolen', 'borg', 'serve', '--umask=077', '--debug']
Remote: zsh:1: command not found: borg
Connection closed by remote host. Is borg working on the server?
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/borg/archiver.py", line 4455, in main
exit_code = archiver.run(args)
File "/usr/lib/python3/dist-packages/borg/archiver.py", line 4387, in run
return set_ec(func(args))
File "/usr/lib/python3/dist-packages/borg/archiver.py", line 134, in wrapper
make_parent_dirs=make_parent_dirs, args=args)
File "/usr/lib/python3/dist-packages/borg/remote.py", line 577, in __init__
raise ConnectionClosedWithHint('Is borg working on the server?') from None
borg.remote.ConnectionClosedWithHint: Connection closed by remote host. Is borg working on the server?
Platform: Linux retropie2 5.10.103-v7l+ #1529 SMP Tue Mar 8 12:24:00 GMT 2022 armv7l
Linux: debian 10.13 
Borg: 1.1.9 Python: CPython 3.7.3
PID: 28539 CWD: /home/pi
sys.argv: ['/usr/bin/borg', 'create', '--debug', '--stats', 'borg@octolen:/Users/borg/BorgRepos/RetroPie2::Friday2', 'RetroPie']

I did add /usr/bin/borg to the Mac's firewall's list of applications permitted to allow incoming connections. What am I missing here?

  • 1
    your question does not belong here ... it is not about Raspberry Pi ... it is a linux question at best
    – jsotola
    Dec 24, 2022 at 19:25
  • 1
    Sure, it is. I want to back up my Raspberry Pi. How do you back up your Raspberry Pi?
    – fpt
    Dec 24, 2022 at 19:32
  • you want to back up your linux computer... if you ran Linux on an HP computer, would you ask the question at an HP site?
    – jsotola
    Dec 24, 2022 at 19:52
  • 1
    Labeling this question as "off-topic" seems to abandon a long-standing precedent. There are numerous questions here on RPi SE that involve backup solutions. The OP's stated objective: setup an automated backup system to backup my Raspberry Pi's data. That sounds very Pi-specific to me. I don't understand his choice of borg, but that should not result in closure.
    – Seamus
    Dec 25, 2022 at 6:20
  • 1
    My recommendation is in my answer below.
    – Seamus
    Dec 25, 2022 at 23:22

2 Answers 2


The Objective: setup an automated backup system to backup my Raspberry Pi's data

I don't know anything about "borg", so this answer will address the objective. If "borg" is a requirement, you can stop reading here.

There is a backup solution that is specific for the RPi called image-backup. It's been around for a while, it is well-supported by the author, and it is easily automated. I have automated my backups using image-backup with a very simple script I schedule as a cron job from my RPi.

There have been several Q&A here on RPi SE that reference it (for example], or you can do your own search.

In my case, I create a "new-from-scratch" backup image every 4-8 weeks, and then update this "master" image using a script I run from the root crontab. I have placed all the image-backup scripts in /usr/local/sbin.

I update my backup images using the following script (also kept in /usr/local/sbin):


# filename: updt_img_bkup.sh
# bash script to update image-backup images
# this script scheduled via root's crontab

# image file name prototype:
# /mnt/SynologyNAS/rpi_share/raspberrypi3b/20220715_Pi3B_imagebackup.img

HOSTNM=$(cat /etc/hostname)\/
IMG_TO_UPDT=$IMG_ROOT_LOC$HOSTNM$(ls -1tr $IMG_ROOT_LOC$HOSTNM | tail -n 1)     # update the latest file
BASE_NM=$(basename $IMG_TO_UPDT)

DRY_RUN=1       # 0 ==> dry-run, 1 ==> update backup image

printf "====> begin log entry for $0 <====\n"
printf "Commence $BASH_ARGV0 at datetime: $(date -u)\n"

# Verify the image to be updated is available:
if [ ! -f $IMG_TO_UPDT ]; then
   printf "\nBACKUP FAILURE: ON $(date -u), $0 FOUND NO IMG FILE TO UPDATE \
AT LOCATION $IMG_TO_UPDT\n" | tee -a /etc/issue.net $LOG_LOCATION
   exit 1

if [ $DRY_RUN -ne 0 ]; then
        # Write an entry to the log:
        printf "$BASH_ARGV0 - begin update of backup image: $BASE_NM, date-time: $(date -u)\n"
        # Update the backup image with the 'image-backup' script:
        /usr/local/sbin/image-backup $IMG_TO_UPDT
        if [ $RTN_CODE -eq 0 ]; then        # updated backup successful
                printf "RESULT: Succesful update of backup completed at: $(date -u)\n"
                printf "Updated backup image: $(ls -l $IMG_TO_UPDT)\n"
        else                         # updated backup failed
                printf "ERROR: image-backup RTN_CODE is $RTN_CODE; $BASH_ARGV0 FAILED to update $IMG_TO_UPDT\n" | tee -a /etc/issue.net
        printf "DRY_RUN invoked; NO UPDATE on $IMG_TO_UPDT\n"
        printf "END DRY_RUN value is: $DRY_RUN\n"
        printf "ENDING DATE-TIME: $(date -u); script: $BASH_ARGV0\n"

One line in the root crontab runs the script above on a schedule. The crontab entry also creates a log. Here's how:

$ sudo crontab -e

# add the following line: 

0 13 * * 0,2,5 /usr/local/sbin/updt_img_bkup.sh >> /home/pi/imagebackup.log 2>&1 

This can easily be adapted to a number of situations; I will leave it to you to get the backup image file (*.img) to your Mac Mini. The *.img file created in this way can be used to do a complete restoration of your system by burning it to an SD card, or it can be mounted in a Linux system for access to individual files. There are two partitions in the image file: a FAT partition whose root is /boot, and an ext4 filesystem whose root is /. /boot can be read and edited on your Mac, the ext4 partition cannot. If, for some reason, you need a backup of specific files that reside on the ext4 partition, I'd suggest you use rsync for that purpose.

  • It looks like it's nice for creating and synchronizing a bootable image, which has its place. But what I'm really looking for is a backup system, not a data synchronizer. And by "backup system" I mean that a new archive is created with each run. This is desirable because if some undesirable change happens to my original data and then gets copied to backup, then I'll still have older archives to refer back to. That's why I want backup and not sync.
    – fpt
    Dec 28, 2022 at 4:10
  • 1
    @fpt: image-backup has the capability to do that. In fact, if you enter only sudo image-backup, you will get a "fresh" image; if you enter image-backup /path/to/existing/image, it will update that image. You may be thinking of a backup rotation scheme. image-backup does not implement a rotation scheme - it only does the backups. In my case, I make a "fresh" backup about every 3-4 weeks, and bi-weekly updates.
    – Seamus
    Dec 28, 2022 at 4:32

There is no need to start "borg serve" manually on the repo server because the borg client invokes that command via ssh and then talks to it via stdin/stdout/stderr.

Remote: zsh:1: command not found: borg

That means that borg is not in the PATH on the repo server (for the ssh session created by the borg client).

So, borg is NOT (yet) working on the server.

https://twitter.com/pi_stack/status/1606668460074958849 < hehe

borg 1.1.9 is rather old btw and only safe if it is a patched version (like in debian). check if you can get a more recent version (e.g. from debian backports).

  • 1
    That was a good suggestion, but doesn't seem to've been the issue: Mac Mini: /usr/local/bin/borg % echo $PATH /usr/local/bin/borg:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/Apple/usr/bin RPi: sudo borg create borg@octolen:/Users/borg/BorgRepos/RetroPie2::Friday2 RetroPie Password: Remote: zsh:1: command not found: borg Connection closed by remote host. Is borg working on the server?
    – fpt
    Dec 24, 2022 at 18:48
  • 1
    The PATH in your user shell is not necessarily the same as in the borg environment. And if your remote says "command not found: borg", you maybe should not assume that your mac is lying to you. :-) Dec 24, 2022 at 23:35
  • You mean like this? borg@Octolen ~ % env HOME=/Users/borg LANG=en_US.UTF-8 LOGNAME=borg OLDPWD=/Users/borg PATH=/usr/local/bin/borg:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/Apple/usr/bin PWD=/Users/borg SHELL=/bin/zsh
    – fpt
    Dec 24, 2022 at 23:59
  • So then how could I check and reconfigure the PATH variable for the environment in which I'm trying to execute borg?
    – fpt
    Dec 25, 2022 at 1:40

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