We're running some 1GB FTP file transfer tests in advance of a larger 40GB transfer and seeing 15x slower performance (450kB/s vs. 7Mb/s) when the 1GB test tar file is composed of small (<100k) binary files (images, pdfs, compressed files, etc.) vs. similarly small text files (jason snippets).
The approach is a passive FTP binary mode transfer via ncftp client to an ncftpd server over the Internet from one datacenter to another, with both datacenters having 100Mb/s WAN links.
Perhaps there is a fundamental misunderstanding, but why would one tar file FTP transfer 15x slower than another of the same size based on content type? Could our firewall be at play here? And, can we have the 7Mb/s version, instead?