scp too slow... is my network wrong?

[anmaxp]

Hello all,

I have a 2pc home network (both running rh 9) and Im having a bit of a problem using scp to copy files between them, turns out scp takes about 5 mins or more to copy a small (1.6mb) file from one pc to the other.

This is really weird, specially since the internet works fine (shared connection) and i can vnc from one pc to the other with no problem also... thanx in advance for ur help!

[Gertrude]

Because you only having issues with that one application being slow over the network, I would first make sure that openssh is the newest version on both computers..

Also another thing you could check just to be sure, but I dont think should be a issue is doing a ping flood to the computer your getting the file from. Just to be sure there is a good connection to it and your not getting alot packet loss, or ranging response times to the host.

as root

ping -f ip.add.re.ss

let that got for maybe 20 seconds then "<ctrl> c" to stop it

and post results..


Another thing that can sometimes can cause slow speeds on a network is if one NIC is operating in full-duplex and the other is in half-duplex. You might wanna check that just to be sure..


Yet another thing that may cause issues is if your HDD on either computer I/O throughput is not up to what it should be. You could check this two ways that I know of:

1.) Install hdparm then as root type:

hdparm -tT /dev/hda

and post the output

2.) Copy a large file to /dev/null and see how long it takes to remove the file:

dd if=large-file-name of=/dev/null

example:

Moo:/home/gert# dd if=test of=/dev/null
0+1 records in
0+1 records out
53 bytes transferred in 0.000364 seconds (145608 bytes/sec)

[henryluo]

you can use other way test the speed(wget...)

[bwkaz]

Yeah, scp does encrypt all network traffic. It might be worth using some protocol that doesn't (like HTTP or FTP), just for testing.

Otherwise, what Gertrude is saying is worth looking into.