WinSCP mega-slowness

gh u3mgh at utanet.at
Wed Mar 1 06:43:33 PST 2006


On Wednesday 01 March 2006 14:15, Daniel A. wrote:
> On 3/1/06, gh <u3mgh at utanet.at> wrote:
> > On Monday 20 February 2006 13:04, Daniel A. wrote:
> > > Hi,
> > > I have the same issue here.
> > > When I use SFTP (WinSCP) to transfer from my Windows XP SP2 box to my
> > > local server, I can only utilize about 1/10'th of the bandwith
> > > (100mbit).
> > > On the other hand, when I use FTP or SMB to transfer files, I can
> > > utilize the maximum bandwith.
> > >
> > > On both boxes, the "symptoms" are the same:
> > > - Lots of available CPU time
> > > - No significant disk I/O
> > > - Quite a lot of available RAM.
> >
> > but SFTP (WinSCP) is a crypted transfer (ssh tunnel)
> > therefor it must be slower than
> > any uncrypted transfer like FTP or samba ....
> Yes, but one tenth? I would understand the speed difference if at
> least the encryption required either a lot of CPU time or memory
> utilization, but the fact is that it doesnt. In fact, my PC is
> practically idle while it's transferring files through sftp.
> 
> I believe that fbsd_user (at a1poweruser.com) is correct about the
> different buffer size being the cause of this problem.
> 

i think that the different operating systems (and their programs)
cause this minimized transfer with a ssh tunnel 
because the transfer run from application to ssh to tcp/ip socket
on one machine and the other way round on the peer and
both sides had to wait for each other (different platforms - different timing)
so the time consumption without really doing usefull


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