unser externer FTP-Server (v1.2.9, default Server off, ein VH mit Port 21) hat das Problem daß ein Upload mit 1,5 Mbit/s geht - der Download aber nur mit 150 kbit/s.
aus:
http://castaglia.proftpd.de/doc/contrib/ProFTPD-mini-HOWTO-BCP.htmlFinally, there are some configure options that can be used to tune your proftpd daemon. All of the --enable-tunable options are available; of particular interest are --enable-tunable-buffer-size and --enable-sendfile. Use of the sendfile(2) function (via the latter configure option) may or may not increase download speeds, but it will reduce disk I/O: sendfile(2) implements zero-copy transfers, meaning that the kernel will read data directly from the file into the socket, all in kernel space; normal read() transfers spend time copying buffers from kernel space to application space (reading the file), and then back to kernel space (writing to the socket). By increasing the buffer size using the --enable-tunable-buffer-size option, proftpd reads and writes data in larger chunks, and makes fewer expensive system calls. Use of this option to set buffer sizes of 8K or more has been reported to drastically increase transfer speeds (depending on network configurations).
cu
stonki