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Re: [Networker] Performance Tuning backup
2007-07-26 12:05:19
Reed, Ted G [IT] wrote:
You have an assumption in your math section that is not valid.
You assume that GigE can perform at 125M/sec. And theoretically,
that's correct. The same way, theoretically, a 100Mb NIC can do
12.5M/sec. However, the reality is that the overhead on a 100Mb means
8-9M/sec is realistic throughput for client data.
And while you'd think that'd mean that a realistic throughput for
GigE then must be 80-90M/sec (GigE=10*100Mb), the fact is that
40-50M/sec is all you can expect to see out of a GigE card, out of the
box, without some level of performance tuning. With extensive tuning,
I've seen people get up to 70M/sec out of a GigE...maybe the
occasional burst higher. But in the cases I've dealt with directly,
we've come to the conclusion that an out-of-box GigE is the equivilent
of 5*100Mb, or half what the specs lead you to believe.
My tests in years gone by bear your figures out. Additionally:
* GigE on fibre is quicker than GigE on copper.
* Solaris gives higher numbers than Windows, perhaps a more efficient
TCP/IP stack.
* When I installed Linux on the same Intel hardware I used to test
Windows throughput I found that the throughput was the same but with
significantly less CPU overhead.
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