SFTP & FTP transfert rate

Hi,

I've made a test on my local LAN to compare the gap between SFTP and
FTP transfert rate.
hardware details:
X linux mandrake 10 box with 100Mb/s lan card, 512Mo RAM, 2,4 Ghz proc
DELL 350
|
X HUB 100Mb/s
|
X Windows XP Home with 100Mb/s lan card, 512Mo RAM, 1,8 Ghz proc DELL
inspiron 8200

Now here is the tests :

fisrt attempt : FTP transfert between FileZilla on the window laptop
and pure-ftpd server on the linux box
The average transfert rate is about 5 MB/s (700 Mo file) B as Bytes

second attempt : SFTP transfert between FileZilla(Winscp3 too) on the
window laptop and sshd on the linux box
The average transfert rate is about 260kB/s !!!!

(the transfert rates seem to be net not brut)

Now my question : why does this transfert rate is so low ??

I'm aware that with SSH the packets are encrypted what meens more data
to transfert but that do not explain the huge difference. A friend
proposed that the limitation could come from the SSH process that
needs a better CPU but i checked my CPU activity during the test on
both sides were not using more than 5 %.

Thank you in adavnce for your explanation

Paul

Paul <(E-Mail Removed)> wrote:

> I've made a test on my local LAN to compare the gap between SFTP and
> FTP transfert rate.

> Now my question : why does this transfert rate is so low ??

The maximum I usually get is 1MB/s when transferring using SSH
protocols. This will vary depending on the speed of both systems, and
the algorithms and keysizes used.

SSH is the bottleneck here. Though I would agree that 200 somthing kB/s
is a bit slow, perhaps you're running low in your entropy pool? Do you
have kernel support loaded for whatever random-number-generator is on
your machine?

--
Cameron Kerr
(E-Mail Removed) : http://nzgeeks.org/cameron/
Empowered by Perl!

Paul <(E-Mail Removed)> wrote:
> I've made the same tests with tow linux box till on 100Mb/s Lan
>
> result:
> FTP transfert rate : 5 Mo/s
> SFTP transfert rate : 1.2 Mo/s
>
> Still same question :why does the SFTP transfert rate is so low ??

Same answer: Encrypted traffic will never be faster than unencrypted
traffic on the same hardware.

That's a reasonable rate, I wouldn't expect any faster on most machines
unless they're _both_ pretty fast.

--
Cameron Kerr
(E-Mail Removed) : http://nzgeeks.org/cameron/
Empowered by Perl!

I've made the same tests with tow linux box till on 100Mb/s Lan

result:
FTP transfert rate : 5 Mo/s
SFTP transfert rate : 1.2 Mo/s

Still same question :why does the SFTP transfert rate is so low ??

(E-Mail Removed) (Paul) wrote in message news:<(E-Mail Removed). com>...
> Hi,
>
> I've made a test on my local LAN to compare the gap between SFTP and
> FTP transfert rate.
> hardware details:
> X linux mandrake 10 box with 100Mb/s lan card, 512Mo RAM, 2,4 Ghz proc
> DELL 350
> |
> X HUB 100Mb/s
> |
> X Windows XP Home with 100Mb/s lan card, 512Mo RAM, 1,8 Ghz proc DELL
> inspiron 8200
>
> Now here is the tests :
>
> fisrt attempt : FTP transfert between FileZilla on the window laptop
> and pure-ftpd server on the linux box
> The average transfert rate is about 5 MB/s (700 Mo file) B as Bytes
>
> second attempt : SFTP transfert between FileZilla(Winscp3 too) on the
> window laptop and sshd on the linux box
> The average transfert rate is about 260kB/s !!!!
>
> (the transfert rates seem to be net not brut)
>
> Now my question : why does this transfert rate is so low ??
>
> I'm aware that with SSH the packets are encrypted what meens more data
> to transfert but that do not explain the huge difference. A friend
> proposed that the limitation could come from the SSH process that
> needs a better CPU but i checked my CPU activity during the test on
> both sides were not using more than 5 %.
>
> Thank you in adavnce for your explanation
>
> Paul

On Fri, 28 May 2004 17:24:22 +1200, Cameron Kerr wrote:

>> FTP transfert rate : 5 Mo/s
>> SFTP transfert rate : 1.2 Mo/s
>>
>> Still same question :why does the SFTP transfert rate is so low ??
>
> Same answer: Encrypted traffic will never be faster than unencrypted
> traffic on the same hardware.

Sure. However, my experience is that the Windows clients based on PuTTY
(such as WinSCP) are a bit slow. Try a Linux-to-Linux transfer. My
K6-500 MHz is capable of doing scp with 3-4 Mbytes/s on a fast network.

--
Morten Bakkedal