Any upload hash checking/comparing software?

[Deozaan]

Every once in a while I will upload some files to the internet as a backup, and when I restore the files back to my computer, I realize that the file is corrupt because my internet connection freaked out during the FTP upload.

Is there any FTP client/server software that will perform a checksum on the remote files and compare them to the local files? Or perhaps a php/website script that could do something like this?

The reason why I'd prefer FTP is because my host provides a special FTP-only backup account (with no web-access to the files) and that's usually where I upload my backups to.

[f0dder]

You can't do a checksum on the remote files without downloading them (unless there's some really funky FTP daemon that has a checksum SITE command, but haven't heard of one).

A guy I know worked on a custom ftp client years ago that would create checksum files for every file you uploaded, with a hash for each chunk of the file so you would only have to re-download corrupt pieces. Dunno if he ever produced even a proof-of-concept, I've never heard of other people doing this, and it would obviously only work for files that you've uploaded with the custom client. *shrug*.

[JavaJones]

Do you have shell access? I reckon you could probably setup a CRON job to make MD5 hashes of all files uploaded to a specific directory/tree if said files did not already exist. Then you could just make local MD5s and download the ones from the FTP to compare if there was ever any doubt.

- Oshyan

[Innuendo]

Globalscape or Rhino software (?) has the feature you want, but you have to be running their software on both ends of the transfer (their FTP server & their FTP client) so I doubt that option would work for you.

[Deozaan]

A guy I know worked on a custom ftp client years ago that would create checksum files for every file you uploaded, with a hash for each chunk of the file so you would only have to re-download corrupt pieces. Dunno if he ever produced even a proof-of-concept, I've never heard of other people doing this, and it would obviously only work for files that you've uploaded with the custom client. *shrug*.

-f0dder (April 14, 2010, 05:48 PM)

That sounds basically like BitTorrent.

Globalscape or Rhino software (?) has the feature you want, but you have to be running their software on both ends of the transfer (their FTP server & their FTP client) so I doubt that option would work for you.

-Innuendo (April 14, 2010, 09:34 PM)

It probably won't, unless I can convince my host to switch to that. It would be great to have an FTP server that would perform a checksum server side to compare with a client that was performing the checksums before it uploaded.