Simultaneously download from an FTP server different parts of the same file with multiple connection

polo :

I want to download a very large file from an FTP server. Is it possible to start downloading from a specific offset? My use cases are: 1. connection dropped during transfer, can I continue the download rather than start over? 2. can I use multiple connections with different offset to download the file faster using multiple connections simultaneously?

I'm working in scala, so ideally looking for JVM libs that offer this functionality. I couldn't find any tools offering this or even evidence for the FTP protocol supporting something like an offset

Andreas :

Is it possible to start downloading from a specific offset?

Yes, if the FTP server supports it.¹

If connection dropped during transfer, can I continue the download rather than start over?

Yes, if the FTP server supports it.¹

Can I use multiple connections with different offset to download the file faster using multiple connections simultaneously?

Yes, if the FTP server supports it.¹

I'm looking for JVM libs that offer this functionality.

Please see Help Center article "What topics can I ask about here?":

4. Questions asking us to recommend or find a book, tool, software library, tutorial or other off-site resource are off-topic for Stack Overflow.

I couldn't find evidence for the FTP protocol supporting something like an offset.

If you look at the full list of FTP commands, the REST command (restart transfer from the specified point) seems on point.

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^{1) You can ask the FTP server what it supports using the FEAT command (get the feature list implemented by the server).}