rsync error: some files/attrs were not transferred (code 23)

What the message looks like

rsync: [sender] send_files failed to open "/var/log/app/current.log": Permission denied (13)
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1338)

Common causes

• The rsync user cannot read source files or directories.
• Files change during the run, such as logs, caches or database files.
• Attributes like ACLs or xattrs cannot be applied on the target.
• The target filesystem cannot store permissions or owners, for example FAT or NFS with root_squash.
• A file disappears between the file list and the transfer, common with rotated logs.

Check

1. Exit code and statistics
   rsync -a --stats src/ dst/ 2>&1 | tail -n 15; echo "exit=$?"Copy
2. Show only the error lines
   rsync -a src/ dst/ 2>&1 | grep -E 'rsync: |failed|Permission denied' | head -n 20Copy
3. Dry run without writing
   rsync -an --itemize-changes src/ dst/ | head -n 20Copy
4. Check permissions along the path
   namei -l /backup/dataCopy

Fix

• Read the individual error lines: code 23 is the summary, the reason is right above it.
• Check read permissions and run rsync as the right user instead of forcing root.
• For changing files, take a consistent database backup first or skip directories with --exclude.
• Only transfer attributes the target supports: -a without -AX, or use a suitable filesystem.
• For backups, 23 is a failure even if almost everything was copied. Do not treat it as success.

FAQ

Can I ignore code 23?

Only if you know exactly which files are missing. --itemize-changes and the error lines show it; for backups 23 is a failure.

Why does it only happen on the second run?

Because files changed during the run or attributes could not be set on the target.