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WinScp (SFTP-3 AES-256) download 10.5 MB/s

FileZilla (SFTP AES-256) download 12.6 MB/s
FileZilla (FTP) download 105 MB/s

Tunnelier 4.4

Tunnelier (SFTP AES-256) download 15 MB/s
Tunnelier (SFTP arcfour) download 24 M/s

I did little test here:

Server: CentOS 5.6 x64 + SSH 5.8p1-hpn13v11 / vsftpd 2.0.5
Network: GigaLan
Client: Windows 7.1 x64 + WinSCP 5.0beta / FileZilla 3.5.1
File: 524 MB

WinSCP (SFTP-3 arcfour) download 22.5 MB/s
WinSCP (SCP arcfour) download 16 MB/s
WinSCP (FTP) download 105 MB/s

Tranton wrote:

I get just the same problem when I try and login to my school's server to transfer something,
Error: ssh_init: Host does not exist
Error: Could not connect to server

Can you connect using any other SSH (SCP/SFTP) client?

Also read this article:
https://winscp.net/eng/docs/message_host_does_not_exist

I get just the same problem when I try and login to my school's server to transfer something,
Error: ssh_init: Host does not exist
Error: Could not connect to server

Today tested on a new Server 2008 R2, 2x Xeon E5620:


FTP over LAN 1GBits/s for comparison:

4.28 was now also slow... checked my speed setting on the NIC and it was set to "Auto" - changed this to 100 Full and am now working normally again (3mb sec)

4.29 is also slow for me, getting ready to uninstall and try 4.28 again

ErikSorensen wrote:

Hi - came across this thread while googling this issue. Just to add my .02 -- I have 3.8.2 installed side by side with 4.3.2 on the same machine - 3.8.2 gets 4300 KB/s while 4.3.2 gets 30 B/s while trying to sftp upload to the same server.

Can you try 4.2.9 for comparison?

i too am seeing very slow speeds when uploading files from my winxp pc to a redhat 5 linux machine (also slow to aix and solaris machines) (14mb in 24 minutes)

Hi - came across this thread while googling this issue. Just to add my .02 -- I have 3.8.2 installed side by side with 4.3.2 on the same machine - 3.8.2 gets 4300 KB/s while 4.3.2 gets 30 B/s while trying to sftp upload to the same server.

By coincidence I have done some tests yesterday too. But I had no luck so far.

I just tested the latest version, WinSCP 4.3.2.

(600mb test file)

California PC download from East Coast OpenSSH server using WinSCP 4.3.2 ~15minutes, high speed around KiB/s

California PC upload to East Coast OpenSSH using WinSCP 4.3.2 ~16minutes, high speed around 640 KiB/s


Sorry :(

Do you have any update on this?

Thanks!

aliengerm1 wrote:

Another dev mentioned it might have to do with sending more packets without waiting on ACK, they called it "pipelining".

I'd guess you've already seen this but if not, its a interesting read.

https://www.psc.edu/hpn-ssh-home/hpn-ssh-faq/

This is partly implemented already:
https://winscp.net/tracker/17

Another dev mentioned it might have to do with sending more packets without waiting on ACK, they called it "pipelining".

I'd guess you've already seen this but if not, its a interesting read.

https://www.psc.edu/hpn-ssh-home/hpn-ssh-faq/

aliengerm1 wrote:

I hate to put you on the spot but do you consider this a priority item or a low level item?

Rather of priority. Which means I'll take a look at it in a week or two.

Thank YOU.

Update: I had a bit of software that had a default of 128kbytes, which autotuned to 1024kbytes for socket receive buffer. I then set default to 2048, then it autotuned to 4096. Autotuned = tcp sliding window adjustment, in the socket receive buffer. That's for download only, that particular bit of software performed poorly when it came to upload, so no good numbers.

I hate to put you on the spot but do you consider this a priority item or a low level item?

Thanks again.

Thanks for your investigation. I'll check it.

I can only make an educated guess and say that I think the problem lies with a too small socket receive buffer.

More research:
I found another tool that has adjustable send/receive buffers. The default it negotiated was 1024kbytes, which was still slow. The ideal for this particular line seems to be 2048kbytes. My guess is that WinSCP has 512 send/receive buffers. Those should at minimum be upped to 1024 in general, and consider makeing that a user adjustable parameter since its useful particularly on large and long lines, aka WAN.

This is a repeat and summary of a related post.

Situation:
PC on one coast of USA
Unix (solaris) server on the other coast of the USA, running OpenSSH_5.6p1-hpn13v10
Ping: 80ms
Network connectivity: WAN network speed - 40mbps

Over long distance (WAN) on a tuned system, WinSCP 4.3.1 using SFTP (protocol ssh-2) caps around 690kbytes** on download and upload. Cipher AES or blowfish does not make a significant difference. (Ciphers make a large difference during local performance where CPU is more of an issue.)

We found that switching to Filezilla removed the download cap, reaching up to 4.4MB/s (40mbps - which was near the limit of the line). Upload was capped at 650kbytes, which has since been removed by the Filezilla devs (Fixed as of 3.3.5)

Speed difference:
Filezilla results: Transfer of 600mb file in 3minutes. 4.4MB/s

WinSCP 4.3.1 beta results: Transfer of the same 600mb file in 14minutes. 689KiB/s