Data sync error?

My normally reliable backup script failed last night. Unfortunately I 
did not print up the non-zero error code, but I received the message:
Error while saving data: Failed sync the slice (fdatasync): Input/output 
error

However, the backup looks to be the correct size, is readable by darGUI 
and the final log messages from the log are:

........
Adding file to archive: /accounts/graeme/Software/list.txt
Saving Filesystem Specific Attributes for /accounts/graeme/Software/list.txt
Adding folder to archive: /accounts/System Volume Information
Saving Filesystem Specific Attributes for /accounts/System Volume 
Information
Writing down archive contents...
Closing the escape layer...
Writing down the first archive terminator...
Writing down archive trailer...
Writing down the second archive terminator...
Final memory cleanup...

which seem pretty normal. Should I be worried?
-- 
Graeme
Machine 'Haydn' running Plasma 5.20.4 on 5.15.43-desktop-1.mga8 kernel.
Mageia release 8 (Official) for x86_64