0.7.0.1 raises rsync RC24 error code

[bcutter]

After updating to v0.7.0.1, the last scheduled raspiBackup failed with

...
Backuperstellung vom Typ rsync gestartet. Bitte Geduld
file has vanished: "/var/lib/apt/lists/partial/archive.raspberrypi.org_debian_dists_bullseye_InRelease"
rsync warning: some files vanished before they could be transferred (code 24) at main.c(1333) [sender=3.2.3]
03-28-2025 05:44:53 ??? RBK0021E: Backupprogramm des Typs rsync beendete sich mit RC 24
03-28-2025 05:44:53 --- RBK0033I: Bitte warten bis aufgeräumt wurde
...

That was never ever an issue on that host - for years. Either v0.7.* got a bit picky-er about that (don't we stop services like apt etc. prior backup start by default? maybe we don't do this anymore since v0.7.*?) or it was a one-in-a-million-coincidence. ...which happens a bit more often looking at the first search machine result (https://forum-raspberrypi.de/forum/thread/63749-raspibackup-fuehrt-keine-backups-mehr-aus-probleme-mit-vanished-influxdb2-dateie/) ;-)

I do not have the RSYNC_IGNORE_ERRORS="23 24" option set in the raspiBackup.conf (but I do on another host - just a test machine - where this always was necessary). At least not (according to previous /usr/local/etc/raspiBackup.conf backups) from 2024-05-20 until today.

I want to track down the root cause for this, ideally with a recommendation on how to solve this issue.

Quick and dirty workaround: add the RSYNC_IGNORE_ERRORS="23 24" config option again.

[framps]

maybe we don't do this anymore since v0.7.*?)

raspiBackup never stops any services per default. You have to define which services should be stopped. Either with the installer or by editing the config file. Please note the installer only presents services to be stopped and started with systemd.

or it was a one-in-a-million-coincidence

Yes ;-)

I want to track down the root cause for this, ideally with a recommendation on how to solve this issue.

The only way to get rid of this message is either to stop the service which deletes the file during the backup run or exclude the file or even the directory from the backup.
The undocumented option to ignore RC24 is the last resort and I strongly recommend not to use this option because RC24 is also returned by other rsync errors. These errors will be also hidden and an incomplete backup may be created without error notification.

[framps]

I did some more investigations about the rsync vanished message and error code. I found this post and others where a lot of folks requested an option to suppress the error when a file vanishes. The maintainer of rsync refuses to add a patch to rsync for reasons explained in the linked thread. But he presented a wrapper script for rsync (rsync-no-vanish) which ignores RC 24. He wrote there exist some rare edge cases when an RC24 is reported and is a valid rsync error (See here). I found various site which complain about this message and use the wrapper script even there exist edge cases which are true rsync errors.

Given this I enabled the option DEFAULT_RSYNC_IGNORE_ERRORS again which I disabled in 0.7.0 and added FAQ59 where I suggest to stop the service or to exclude the file first and use option DEFAULT_RSYNC_IGNORE_ERRORS as a last resort.

[bcutter]

I see. The core issue is that for rsync it seems to be impossible to distinguish between an "actual issue" and a file which just changed during sync progress.

So it is up to the user to decide if it's an issue or safe (acceptable) to use the ignore option.

So just to make sure: is using RSYNC_IGNORE_ERRORS="23 24" the same as using the re-added DEFAULT_... config option?

[framps]

Sounds like you use RSYNC_IGNORE_ERRORS already because the code wasn't deleted and can be used without my fix if you know how :-) . This settings is now available officially again with the config option DEFAULT_RSYNC_IGNORE_ERRORS.