Re: Copy Times for Remote Copy

[Reenen Kroukamp]

On Thu, Jan 29, 2004 at 07:42:19PM -0400, Andrew Greenwood wrote:
> Hi,
>       I am writing to inquire on what speed should be obtained with a
> copy: from a network cfservd server. The 2 systems are on a 100MB
> backbone. I am copying approx 250MB (27185 files) and it is taking
> +22minutes. I am using the purge feature as I would like to keep an

So, 250MB in 22 minutes gives you: 250/(22*60) = .189 MBytes/s

A 100Mbits/s network card, in bytes provides 100/8 = 12.5MBytes/s. You
also have some ethernet overhead, tcp overhead, etc. So you can
probably get a max of just under 10MBytes/s throughput. Using
scp to my laptop, ie with encryption overhead on a not too great machine,
I can get:

        9 reenen:/home/reenen% scp 172.24.158.234:bigfile .
        reenen@172.24.158.234's password: 
        bigfile                 100%  100MB   4.2MB/s   00:23    

Obviously there is something seriously wrong with your copy. My guess
is that your network cards are not set to 100M Full Duplex. If you are
running Linux, you can check with mii-tool:

reenen:~# mii-tool 
eth0: negotiated 100baseTx-FD, link ok

If it is 100baseTx-FD on both sides, try testing with eg ftp to
see what your throughput really is. You can also try using an
app called ttcp or some variant thereof.

-Reenen

-- 
Reenen C Kroukamp <reenen@qualica.com>
Qualica Technologies (Pty) Ltd
http://www.qualica.com/