Hi,
I have an “ahem ahem Seedbox” which has an sftp.
What I simply want is to sync files from this seedbox to my raspberrry pi.
ofcourse this needs to happen automatically so that its setup and forget.
Reason for this request :-
my home networks speed is good but sometimes it goes too damn slow. so I want to download my “files” whenever I have bandwidth and watch it later as its already on my pi and not somewhere on cloud.
Noob here 
thank you.
You mean you want an SFTP server on the DietPi system?
If you have the OpenSSH server installed, it has SFTP included, with Dropbear you can install one, e.g.:
apt install gesftpserver
ln -s /usr/libexec/gesftpserver /usr/lib/sftp-server
Connections via SFTP should then work OOTB just like you would do for SSH, using username and password or authentication key.
theoretically you can create a file system export on DietPi (NFS or Samba) and mount this export to your Seedbox. On your Seedbox you could store files directly on the mounted file system. Just as on idea
Joulinar extactly what I want to do but that drive is on seedbox io (not promoting) so I cannot nfs or samba on that.
is there a possiblity to :-
A - let raspberry pi check this sftp server automaticlly (I can setup username and password)
b - download new files if there are any
Example of such tool that exist is rclone which allows you to sync files but has to run manally on pi
My Idea was the other way around. create a NFS server on DietPi and have it mounted on your Seedbox. This way you could store/download files directly into RPi.
DietPi themselves did not have a feature to automatically connect to sftp server and check for new files. I guess you would need to develop an own script doing so.
DietPi has a tool dietpi-sync allowing daily syncs but this would require to have a file system mounted from the seedbox. But as I understood, you are not able to create any exports on that device.
Figured a way out. Two ways actually
Install xrdp and then install filezilla gui and connect to ftp and each time you have new files, remote login and push downloads
2- install aria2 and copy paste download liks there. I anyways have a permanent reverse ssh setup which means I can remotely acess aria2 and add links.
Imma use 2nd one as it remove xrdp which has too many dependency.
Ofcourse it’s not that automated but better than waiting for it to stream.
Thanx guys