I’m observing a strange behaviour with my proftpd ftp server. Duplicati writes a lot of “0 byte files” while slowly uploading the freshly generated backup files. In parallel, it also writes the 50 MB archives and the rest of files it wants to. The connection is ftp-ssl. During the phase “verifying backend files”, I’m looking “live” at the state on the ftp server changing and see it deletes the “0 byte” files one by one, each taking 5-10 seconds to get deleted by Duplicati. I remember that before the “ftp ssl” bugs came up early this year before the final stable release that the slow downs started. My machine is Win11 x64 24H2 with latest CU applied.
Could you please shed some light what’s happening? I guess adding and removing a hundred 0 byte files is not normal expected behaviour? Can I improve something with my setup or ftp settings?
Other apps can transfer via ftp-ssl about 70 mbyte/sec.
Your system can shed some light with About → Show log → Live → Retry or using options log-file=<path> and log-file-log-level=retry. You can also look in Complete log section of a job log to see if RetryAttempts is kind of high. Failed uploads get retries, and original files that failed get deleted later. Maybe that’s what’s going on, but next question is why upload failed. Regardless, let’s first see what the pattern is behind empty file uploads. Getting a screenshot like you did can work with the log, e.g. you can find file name in a log.
It’s strange that creating a new folder on the FTP server and pointing a freshly created backup job at it throws “test file corrupted” error and leaves a tmp-file on the storage. But: the user which is signing in has readWrite access, I even set the user account as the owner on the whole folder structure (to be safe) and chmod’ed to 0777. If I skip the connection test, the job runs fine, files are written, no complaints. But it takes long and temporarily produces those 0 byte files. The network connection is LAN and known as stable from my other data hungry transfer apps.
From the Log:
“RetryAttempts”: 219,
Indeed, it’s high, but why? WinSCP transfers quite fine to this FTP server.
