I'm running into an issue with using Net::FTP (latest version 2.77) to transfer files to a remote host where a process is waiting to take the file and feed into some other system.

The remote process does this every 5 minutes but ignores files that were modified in the last 0.2 seconds (that's right, 1/5th of a second). The problem is that for some reason the transfer seems to halt or slow down a bit and no data is transferred for several seconds and during this time the process picks up the incomplete file and removes it.

The weird thing is that manually using the ftp binary the file seems to transfer fine. I've tried messing with all of the Net::FTP switches (Active/Passive, different Blocksizes) and nothing seems to help.

What's also weird is that the file seems to transfer fairly quickly at first and on occasion a bit into the transfer. Like 300-500k will go up immediately, but then it slows down to where the file size is only increasing by 2,896 bytes every several seconds.

It doesn't seem to happen when I try sending the file to a different remote host, but since a regular manual ftp transfer works with this host I don't know what to think. Some combination of Net::FTP and possibly a slow or wonky connection?