Perl SFTP 真的很慢

Question

I'm using the perl Net:SSH2 library to do SFTP. It works well enough but is super slow. It starts off being 7x slower than the link speed (something I could handle) but pretty much as soon as it has transferred 2MB of data it drops to being 1000x slower. Here's a cut down version of my code. I used this Linux command to create a 10M file of random data dd if=/dev/urandom of=10M.dat bs=1M count=10 . For anyone who would like to run the code please enter details for server, user, password etc.

#!/usr/bin/perl

use strict;
use warnings;
use Fcntl ('O_WRONLY', 'O_CREAT');
use Net::SSH2;
use Time::HiRes qw(gettimeofday);

my $server = 'myserver';
my $username = 'myusername';
my $password = 'mypassword';
my $remoteFile = 'delme.dat';
my $localFile = '10M.dat';

my $ssh = Net::SSH2->new();
$ssh->connect($server) or die('Failed to connect to remote server for sftp');
$ssh->auth_password($username, $password);
$ssh->auth_ok() or die('Invalid username or password');
my $sftp = $ssh->sftp() or die('Ahhh!!');
open(my $localHandle, '<', $localFile) or die($!);
my $remoteHandle = $sftp->open($remoteFile, O_WRONLY | O_CREAT) or die($sftp->error());
my $tran = 0;
my $t = gettimeofday();
while(my $line = <$localHandle>)
{
  print $remoteHandle $line;
  $tran += length($line);
  my $newTime = gettimeofday();
  if($newTime - $t > 1)
  {
    print 'Speed is ' . ($tran / ($newTime - $t)) . "B/sec\n";
    $t = $newTime;
    $tran = 0;
  }
}
close($remoteHandle);
close($localHandle);

Answer 1

Support for SFTP in Net::SSH2/libssh2 is suboptimal.

Use Net::SFTP::Foreign instead (with the Net::SSH2 backend Net::SFTP::Foreign::Backend::Net_SSH2 if you are on Windows).

Answer 2

I hope you are facing the Session Re-Keying issue by OpenSSH as mentioned in the below link.

http://crashingdaily.wordpress.com/2007/02/20/a-workaround-for-netsftp-hanging-on-large-transfers/

The link has a fix for this problem as well.