rsync exited with code 23

[hsrthe4th]

I updated from 2.14.43 to 2.15.0 and for some of my containers I get the following in my logs:

INFO: Stopping appname...
INFO: Starting API on port 8069...
TRACE: Using current time for date formatting since USE_CONTAINER_BACKUP_DATE=true
TRACE: Destination directory '/app/destination' READ/WRITE access verified
INFO: Backing up appname...
DEBUG: RUNNING: 'rsync -raq /app/source/appname/ /app/destination/2026-05-22/appname/'
ERROR: rsync exited with code 23 for appname
INFO: Starting appname...

When I check the backup folder the only files missing are the symlinks (which i expect to be skipped)
I also tried 2.19.6 with the same result.

Adding the following custom rsync argument stopped the error, but I want to make sure I'm not masking an issue.
RSYNC_CUSTOM_ARGS=--no-links

[Minituff]

Acknowledged, let me let look into this

[Minituff]

Okay I checked this out. Your workaround is correct and is not masking any real issue.

What's happening

rsync exit code 23 means "partial transfer due to error". In this case it fires because the default rsync arguments include -a (archive mode), which implies -l — copy symlinks as symlinks. When the destination filesystem doesn't support symlinks (e.g. SMB shares, FAT/exFAT volumes), rsync can't create them and exits with code 23. All regular files are transferred successfully; only the symlinks are skipped, which matches what you're seeing.

Your workaround

RSYNC_CUSTOM_ARGS=--no-links overrides the -l flag from -a and tells rsync to skip symlinks entirely rather than fail on them. This is the correct fix for this situation :)

Fix in the next release

I improved the error message for exit code 23 so it now explains the symlink cause and points directly at the workaround:

rsync exited with code 23 for <container> (symlinks may have been skipped — use RSYNC_CUSTOM_ARGS=--no-links to suppress)

This will be included in the next release. In the meantime, RSYNC_CUSTOM_ARGS=--no-links is the right solution.

#686

[Minituff]

This will be included in v2.20.0 https://github.com/Minituff/nautical-backup/releases/tag/v2.20.0

[hsrthe4th]

Awesome, thank you so much for maintaining this tool.