Re: local network capability scanner?
On Friday 07 February 2020 06:24:10 Jeremy Nicoll wrote:
> On Fri, 7 Feb 2020, at 07:04, Gene Heskett wrote:
> > But file moves to/from the machines in the garage seems to indicate
> > theres a slow connection of around 10Mb/s someplace in that path.
>
> Later you said:
> > But on really big writes, the ssd's decay to around 17-20 mb/s.
>
> Surely here you meant MB/s?
>
> If the SSDs will take data at 17-20 MBps then that will need more
> than just (17-20) * 8 ie 136-160 Mbps data to be transferred across
> the network, as far as I know. There's protocol/control data that
> is passed around as well.
>
> In the past I found it simpler to multiply / divide by ten, so for 17
> MB to pass across a network I'd assume the network would move
> approximately 170 Megabits. Maybe things are more efficient now?
>
> Anyway if SSD speed is the issue, your network is presumably
> moving nearer 170-200 Mbps to feed the disks at their max
> rate.
>
> That's nearly 20 times the "slow" data rate you mentioned in
> your original question.
I was trying different ways to move a kernel src to the pi for making and
also reached the conclusion that mc was for some reason terminally slow
at unpacking an .xz kernel and writing the unpack across the network. It
was promising me a 43+ hour ETC. And was showing figures when it updated
the screen here as 4.3 kilobytes/second? Really?
So I stopped that, killed the partial copy, backed out and copied the
whole image to the pi in just 2 or 3 minutes, with mc, then unxz'd it on
the pi in maybe 3 minutes. Made sure it was set for arch/arm with a
bcm2835_defconfig, verified it said fully preemptible and turned off the
wifi. Then built the realtime kernel in around an hour, installed it
and its been running since yesterday. Best kernel I've built yet.
Latency about 16 microseconds. Sweet even.
So maybe bit rot in mc? DIIK. But the job is done, and in a day or so,
when I know its stable, I'll put the output up as a tarball on my web
page for others to use.
Too bad debian does not support the pi's past a pi3.
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>
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