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Horms wrote:
> My (informed) oppinion is that the main performance advantage of using DR
> over NAT is derived from return traffic not having to return through the
> box.
When I compared DR (using Julian's martian patch, which allowed the director
to be the default gw for the real-servers) and NAT, at the same packet
throughput, the load average was 5 on the NAT director and the keyboard
and mouse weren't responding anymore, while the DR director had low load
average (<0.1 I think) and the mouse and keyboard responded just fine. I assume
the rewriting of packets in NAT is the main load on the director. The same
CPU can push the VS-DR packets through without any apparent effort.
I used top to watch the load average. There have been comments here that
top doesn't report CPU usage by the kernel and may not be a useful tool
for comparing load for kernel bound CPU usage against user land usage,
but the difference in mouse/keyboard response was clear. (With top
I thought "system" displayed kernel usage so I'm not clear on the problem
with top).
Joe
--
Joseph Mack PhD, Senior Systems Engineer, Lockheed Martin
contractor to the National Environmental Supercomputer Center,
mailto:mack.joseph@xxxxxxx ph# 919-541-0007, RTP, NC, USA
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