Kris Harris wrote:
> Hello, trying to track down this problem. Between two computers
> (gutowksy,ramsey), I get quite reasonable access via web (wget measures
> 578.09 KB/s, with ramsey serving), but when transferring via sftp or
> scp, the access crawls to a halt (starts at 30 kb/s then stalls, jumps
> to 30 kb/s then stalls ...). It takes 1 min to transfer a file via wget,
> but 3/4 of an hour via sftp!? Iperf also measures a reasonable
> connection rate between the two)
>
> the problem persists from various boxes running a range of openssh
> versions connecting to gutowksy (can't transfer in reverse using
> ramsey's sftp-server which works, because it's behind a firewall I don't
> control ...). So, it seems that the OpenSSH_3.5p1 pat OpenSSH_3.*
> running on gutowsky is failing somehow (installed as corresponding
> redhat package).
> Anyway, I then compiled a new version (openssh-4.2p1.tar.gz) and ran it
> on a different port (just so I don't lock myself out - gutowsky's
> several hundred miles away!) - but found no change at all. Any ideas?
>
> p.s. I saw the message-list-archive post about slowness on solaris,
> and tried altering misc.c to become:
> /* disable nagle on socket */
> void
> set_nodelay(int fd)
> {
> int opt;
> socklen_t optlen;
>
> return;
>
> ...
>
> }
>
> -> i.e., I just through in the return as suggested (to jump out of
> subroutine?)
>
> [EMAIL PROTECTED]
> SDF Public Access UNIX System - http://sdf.lonestar.org
>
It seems to me as a problem of compression. By default, ssh activate
compression. Compression is good through internet, but between hosts in
the same network, it's catastrofic. Try do deactivate the compression.
It will get better. But not THAT better. To achieve very good speed
you'll need to deactivate the cipher of ssh, and trying to decrease the
load on both peers, can be very handy. But, if you don't need the
security of ssh, i do always transfer using netcat, or something
similar. It can achieve very high speeds.
My regards,
Giancarlo Razzolini
