[geeks] Network Slowness

[Caleb Shay]

On 5/24/07, Sridhar Ayengar <ploopster at gmail.com> wrote:
> Patrick Giagnocavo wrote:

>
> > What protocol are you using for transfers?  SSH? FTP?
>
> OpenSSH SFTP using Blowfish ciphers.
>

SSH has a massive overhead in processing, data size, and checksumming,
you can't use that for your testing.  For raw throughput, use
something like netcat

host1# nc -l 1111 > /dev/null

host2# time dd if=/dev/zero bs=1M count=1024 > /dev/tcp/host1/1111

(or pipe it into netcat host1:1111, I believe the /dev/tcp thing is a bash-ism)

I work for a company that makes network backup software for virtual
machines, I've done every test under the sun for checking network
throughput :)  You will almost never see more than 20 MB/s on
SSH/SCP/SFTP transfers, not matter how fast your media is.

Cheers,

Caleb