On Wed, 12 Sep 2007 13:32:12 GMT, Jack Snodgrass <jacks_temp_id_bf2142@verizon.net> wrote:
> On Tue, 11 Sep 2007 23:02:37 -0500, Ignoramus26973 wrote:
>
>> I installed a gigabit network switch and a gigabit enabled laptop wifi
>> adapter (with gigabit, obviously, available on ethernet ports only) in
>> my house.
>>
>> Two computers in my home are connected to the switch and one (laptop)
>> to the wifi adaptor.
>>
>> The highest possible speed of a gigabit connection is about 111
>> megabytes per second.
>>
>> Naturally, I did some tests with a noncompressible 1 gigabyte long
>> file (fragment of some gzipped file exactly one GB long).
>>
>> My first test was to scp files from one computer on the switch to
>> another. Here, I was disappointed as the highest speed was only 22
>> megabytes per second one way and 46 another way. About 20 and 40
>> percent of maximum.
>>
>> Then I tried using HTTP to transfer the same file (both computers are
>> webservers). To my huge surprise, it made a world of difference and
>> the transfer speed was 111 or so megabytes per second.
>>
>> So, now I have a dilemma, I have a fast pipe, but scp is not fast
>> enough (given my CPU) to encrypt/decrypt so much data.
>>
>> I tried something else, which is doing wc -l on a NFS mounted drive
>> (same two computers). It was UNBELIEVABLY slow and the load average on
>> the NFS server shot WAY up. Transferring a 336 MB file took 157
>> seconds, or about e megabytes per second (vs 111 mbps that I achieved
>> with HTTP).
>>
>> So, the conclusion is, HTTP is fast (no wonder), SSH is "medium",
>> and NFS is "slow, very bad".
>>
>> The connection to laptop is a disappointment in its own right, since
>> even with all-ethernet connection, I get about 3 megabytes per
>> second. I think that I need to pull a new wire in the wall.
>>
>> So, the short of it is that there is much work to be done.
>>
>> i
>
> you didn't mention Jumbo Frames.
>
> IF ( BIG IF ) your Gigabit hardware supports 9K MTUs, you can get
> a big boost if you set your MTU to 9000 on your nics.

I think that it does support jumbo frames.

> I'll post some numbers from my setup in the next couple of days.

How do you set MTU? That would only work for local destinations,
right? It would not work for connections outside of my home LAN?

i