Slow uploads when downloading

[guillaumesoucy]

Why don't you take the time to read the documentation, follow the link provided and understand what you're doing?
http://www.proftpd.org/docs/directives/linked/by-name.html
http://www.proftpd.org/docs/directives/linked/config_ref_MaxConnectionRate.html
http://www.proftpd.org/docs/directives/linked/config_ref_SocketOptions.html

Using the google link above, you're tweaking the TCP stack for all the services.
As general rule don't use sysctl when simple auxiliary parameters could probably do the trick (and are easy to remove).
Try to make it simple first, and avoid tweaking Freenas especially when you don't know what you're doing.

Ok but this is commands I need to enter in the terminal? For set the send and recive buffer size?

 

[SmallGuy]

Ok but this is commands I need to enter in the terminal? For set the send and recive buffer size?

No,
in the FTP service GUI settings, in advanced mode, there is an area call "auxiliary parameters", where you can add extra parameters. In fact, under the hood, this area consist in adding lines in proftpd.conf.

Not sure it will solve your trouble, but I think this is what you want to try.