Performance issue in SFTP , CygWin Server

Corinna Vinschen
Wed Oct 5 16:21:00 GMT 2011

On Oct  5 06:41, BhavyaMadiri wrote:
> Our application downloads files from various source systems to our server. We
> have Red Hat Enterprise Linux (RHEL) 5.5 with Advanced Platform version on
> our server. Windows sources system (SRC1) , has Windows Server 2003 on their
> server that hosts Cygwin. They recently moved from FTP to SFTP. They are
> using Cygwin to support SFTP on Windows. The Cygwin setup version is 2.738. 
> During sFTP load testing with SRC1, we encountered significant performance
> issue. Transferring 120K files of total size 58GB takes 4.5 hours using FTP
> but it takes 28 hours using SFTP. 

I'd always expect some performance hit when using sftp compared to ftp,
in the order of 8 to 12 hours in your scenario, but 28 hours sounds a lot
compared to 4.5 hours.

What network connection do you have from your client to SRC1?  Gigabit

Are the 58 Gigs files located on a local disk, or are they on a remote
fileserver?  If remote, what server and what underlying protocol, SMB or

> We have not encountered any performance problems with downloading files
> (same number and size ) from unix/linux systems using SFTP. 
> We suspect this performance issue to be related to Cygwin. 

Unfortunately we don't know your Cygwin you're using on SRC1.  Please
send a cygcheck -svr output as per
Did you try a recent Cygwin snapshot from ?


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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