| Bill Todd 2005-02-07, 5:45 pm |
| jtsnow wrote:
> Im doing drive image backups over a 100baseT LAN using Norton Ghost from a
> PC P4 w/XP to a network storage device.
> Looks like the transfer rate over LAN is about 25 Megbit/s and LAN shows 25%
> utilization and CPU about 50%. Drive is only being accessed about 1/3 the
> time so drive is not limiting the data transfer.
>
> Is 25 Mbit/s about the best one can reasonably expect to get on a 100 baseT?
> Even at that rate, a 44 Gig backup can take a few hours.
>
> Are there ways to easily tweek the LAN to get significant transfer rate
> performance improvements? Or is 25% utilization the best I should expect
> on a 100mb/s LAN?
No. I've seen over 96 Mbits/sec using TPC/IP ('100 Mbit' refers to the
net bandwidth *after* 8/10 encoding overhead - if I've got that right -
is taken out: the actual wire bandwidth is more like 125 Mbit). But
I'm no network expert and I wasn't the one who set up the configuration:
things like jumbo frames and a good-sized 'window' (and/or credit
allotment, which may be something different) will likely help, though -
and make sure that you're also not being constrained by the load being
imposed on your processor to handle the packets (if you still are after
doing everything else possible, you'll need more hardware assistance
from your NIC).
- bill
|