[rhn-users] RE: rhn-users Digest, Vol 30, Issue 26

[Chris Jackson]

Dan Hunter wrote:

> I regularly move large files from a windows XP machine to a Fedora 
> Core 5 machine.
> To avoid bothering other network users, I purchased two Linksys EG1032 
> gigabit ether net cards.
> The cards have been installed.  a direct PC to PC gigabit cross over 
> cable connects them.
> A separate set of IP address have been set up.
> I can verify that data is being transfered over the gigabit cable with 
> windows task manager.
>  
> Transfers over the 10/100 link show up at 82 or 83 percent - about 80 
> Mbps.
> Transfers over the gigabit link show up at 20 to 26 percent - about 
> 230 Mbps.
>  
> What do I have set up wrong?
>  
>

You said you were moving files between a FC5 box and a Windows XP box. Keep
in mind that by default, XP Pro reserves quite a bit of bandwidth for QoS.
There are registry tweaks out there that disable or remove QoS and give you
that bandwidth back. 

 Also if you're transferring between two _desktops_ the performance will
probably be slow. While both os's will cache to ram and transfer from that
cache, eventually you see a bottleneck appear when the cache is emptied and
the hard drive becomes the limitation. 

 The most accurate and useful way to measure something like this is by
transferring to and from a SAN or other attached, high performance storage.
We have an Intransa unit populated with 10 SATA drives in a raid 10 array,
and we can get wire speeds on it via gigabit from nearly any machine in the
building. However, transferring from workstation to workstation we see the
same bottlenecking that you do.