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Re: Re: FTP upload speed problem and buffer size

From: Ivan Makale <>
Date: Wed, 10 Oct 2007 17:07:31 +0200

> Date: Tue, 9 Oct 2007 10:01:30 -0700
> From: Dan Fandrich
> Subject: Re: FTP upload speed problem and buffer size
> To:
> Message-ID: <>
> Content-Type: text/plain; charset=us-ascii

> There's no direct equivalent, but CURLOPT_BUFFERSIZE is set as a side
> effect
> of --limit-rate.
> curl can sometimes try a couple of different FTP modes before
> finding the correct one to use which will cause a measurable slowdown
> a high-latency connection. If you know which one is usable you can
> curl use it directly (e.g. --disable-epsv, --ftp-port, --ipv4).
> Something similar holds for the CWD method as well (--ftp-method), and
> Nagle algorithm can also increase latency (--tcp-nodelay).

I tried with various options you mentioned and other, without
performance improvement. The problem is not the connection time but the
transmission time. Just to give an idea:

- with command line FTP about 500 kbytes/sec
- with curl about 70 kbytes/sec

Forcing the buffer size of command line FTP to the same of curl (thas
is, I suppose, 16384 bytes), with "ftp -w 16384 ...", I get about 250
kbytes/sec, again significantly faster than curl.
Active or passive FTP doesn't change the speed.
O.S.: Windows 2003 Server. I tried both with curl 7.15.1 and 7.17.0.

Thank you and good bye, Ivan Makale
Received on 2007-10-10