[mythtv-users] 1TB USB $225 US
David Brodbeck
gull at gull.us
Mon Feb 11 19:49:31 UTC 2008
On Feb 11, 2008, at 11:27 AM, John Drescher wrote:
> I believe I have got 980Mbit/s (using netperf) between 3 year old AMD
> TYAN motherboards and a netgear 24 or 48 port gigabit switch with that
> was in use. But this is much lower (300 to 700Mbit) if you connect to
> systems with GBit PCI cards (stay away from realtek).
Yeah, I've gotten very close to the theoretical max using servers with
on-board Broadcom Tigon 3 chipsets, too.
Blasting bits out at that speed isn't that hard. But reading/writing
bits to/from a disk *and* blasting them out at the same time is much
tougher. The system bus can easily become a limiting factor,
especially if software RAID is in use. That doesn't mean Gigabit
doesn't live up to its promises, it just means the bottleneck is
elsewhere.
This is an old story, though. In the days before switches you would
almost never get more than 80% of a 10baseT network's rated speed
unless you only had two machines on it. Same with 10base2. :) The
name referred to the signaling rate, not necessarily how fast you
could shift real bits.
I think the most egregious example was "56K" modems, which couldn't
*ever* run more than 54K due to FCC regulations. In real life speeds
above 49K were rare.
More information about the mythtv-users
mailing list