I run an Owncloud server, for me and some of my friends. Apart from updates, which are 90% unreliable, it actually does its job. According to the manual I backup my server to a separate, mounted drive using rsync. Of course, as a cronjob, which partly gives me this message:

rsync: mkstemp "/backup/owncloud/data/folder/files/apple + pie /._DSC1234.jpg.50x57O" failed: No such file or directory (2)
log entry

At first, I assumed that the file had been removed during the backup and ignored the message – static noise, so to speak. However, in the last few messages, they became more and more frequent, making it less likely that all these files would be deleted during the backup. At a second glance, you can see that the paths all have spaces. Rsync cannot handle non-unix-like paths. But since my friends create these paths (possibly unintentionally), a fix is needed.

A look into the manual of rsync fixed it for me:

-s, --protect-args          no space-splitting; wildcard chars only
Excerpt of the manual

Once again I have learned that one should also look carefully at the small daily things. 😉