7.1-PRERELEASE : bad network performance (nfe0)

[pete wright]

On Mon, Sep 29, 2008 at 2:03 AM, Holger Kipp <hk at alogis.com> wrote:
> On Sun, Sep 28, 2008 at 06:30:03PM -0400, firmdog at gmail.com wrote:
>> No....you misunderstood.  The 7.1 box was connected to a 5.4 box doing a 50GB
>> data transfer over rsync.  Both nics were 1000 full duplex with a crossover cable.
>> The speed performance was terrible and I could only get up to 10 Mb/s and there
>> was NO switch involved.  I believe there is a problem or bug involved with the
>> driver.  Have the drivers or stack been updated in 7.1?  What else can I provide?
>
> Hi, I only flipped through the messages in this thread, faintly remembering someone
> writing something about ssh. Anyway, if you're copying using ssh (scp, sftp), then
> the transfer rate is much less than what you'd expect - due to the encryption/decryption
> overhead (unless you have hardware acceleration on both sideds).
>

FWIW I think the general issue for the ssh suite of tools is the
compiled in window size is not tuned for large transfers like this:
http://www.psc.edu/networking/projects/hpn-ssh/theory.php

we use a propritary tool called aspera to overcome these issues when
moving large amounts of data b/w remote sites on our WAN:
http://www.asperasoft.com/products/scp/index.html

the encrytp/decrypt overhead should be pretty minimal on modern
hardware, so i would not expect that to be the first bottle neck you
run into.

-pete

-- 
~~o0OO0o~~
Pete Wright
www.nycbug.org
NYC's *BSD User Group