TScSFTPClient download speed

[egrobler]

Hi,

I am using TScSFTPClient to download files from a ftp server (sftp)
When using the popular WinSCP client I get download speeds of 4000 KB/s but with TScSFTPClient only about a 5th of that.

Any suggestions how I can improve download performance?

I use
FFtp.ReadBlockSize := 1024*256;
FFtp.WriteBlockSize := 1024*256;

Best Regards
Eric

[ViktorV]

Please set the properties ScSFTPClient.ReadBlockSize and ScSFTPClient.WriteBlockSize first to 32768, and then - to 65536. Then check the difference in performance

[egrobler]

I already used a larger blocksize.
After 64K the blocksize makes no difference.
A 200MB files takes much longer to download with DevArt than WinSCP.
Compression also does not make a difference, (I download binary files)

Any other settings I can try?

Code: Select all

	
Program BlockSize seconds
WinSCP          ?      38
DevArt      16384     334
DevArt      32768     192
DevArt      65536     121
DevArt     131072     120
DevArt     262144     123

[ViktorV]

We have tested SecureBridge components and they show higher performance in comparison with WinSCP. To investigate the issue, if it is possible, please provide us access to your SFTP server.

[egrobler]

if it is possible, please provide us access to your SFTP server.

Hi Viktor, I really appreciate the professional help and support from Devart.

I send you a small demo project that downloads files from our ftp server to [email protected]

Thanks & Regards
Eric

[ViktorV]

Test of your sample resulted a difference in performance between SecureBridge components and WinSCP: +/- 5% depending on each test run. Please specify the exact versions of SecureBridge and WinSCP client you are using.

[egrobler]

Hi, I am using
WinSCP version 5.7
and SecureBridgeVersion 6.6.9 with Delphi XE2.
I get similar results from Germany or Ireland.

The difference for me is much greater, more than 3x slower:

[ViktorV]

Thank you for the information. We will investigate this behavior of SecureBridge. We will inform you when we have any results.

[egrobler]

I am impressed with the excellent support you give to your customers.

[snorkel]

Is it possible the nagel algorithm is enabled in SB?
I know that if that is enabled it will cause massive slowdowns on smaller data sizes.

[egrobler]

Hi Snorkel,
Thanks for the info on the Nagel setting.
From what I just read it seems to affect performance on small packets or when downloading lots of small files.
At the moment the problem is that other ftp clients seems to be much faster than the devArt control.

Regards
Eric

[egrobler]

Any progress on this issue?

Regards
Eric

[ViktorV]

We are investigating the issue and will notify you about the result as soon as possible, but we can't tell any timeframe at the moment.