tail -f /usr/local/nagiosxi/var/components/scheduledbackups.log
04-07-2015 11:26:01 DEBUG: Running scheduled FTP backup ...
04-07-2015 11:26:01 DEBUG: Sending create local backup command to CmdSubsystem
04-07-2015 11:50:10 ERROR: Scheduled FTP Backup Failed: Local file to transfer does not exist
While getting the error "04-07-2015 11:50:10 ERROR: Scheduled FTP Backup Failed: Local file to transfer does not exist", the backup was in fact still running. It took another 8 minutes before the local backup was created. So Like I said before I'm pretty sure the script is trying to ftp while the backup is not yet finished...
How long does it usually take to do the local backup? You can try removing "half-way-done" backups from the "/store/backups/nagiosxi/" (if you have any), then specifying a timeout for the scheduled backups by adding the following line to "/usr/local/nagiosxi/html/config.inc.php":
Last time I check, it was about 29 minutes it took to complete. But as said, it seems to me the local created backup is in fact complete. It is just trying to ftp before the backup is completed, hence the file does not yet exists.. I'll test you solution tomorrow though.
Willem, just FYI we had the same problem you're having but with SSH. We don't use FTP, we just SSH our backups to another server, but our backup also takes awhile (~40-60 minutes) so it would close the SSH session before the backup was completed. I modified the backup timeout option to something like 90 minutes and that solved our issue, so hopefully it'll work for you and FTP as well.