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billybangleballs
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webserver clustering

Sun Oct 21, 2018 6:31 pm

I have 4 raspberry pi2 and and orange pi R1 as a load balancer all running apache2.
This is powered by a 10 amp 5 volt psu.
How many more pi2 could I add to the cluster before 'only 10 amps' became an issue?
Would swapping the pi2 out and replacing them with pi3 be advantageous or would a go faster stripe on the case be a better investment?
There is also a 5 port 10/100 hub in the box, which would need swapping for one with more ports.
The networking is 100mbit and my upload to the intarweb is 20mbit fttp with lots more down. ;)

It appears from the limited testing that I have done, that the main current draw is at switch on, when everything boots up together, the rest of the time it is just ticking over, nothing like a serious load has been put on it as yet, I was going to wait until I had a really funny cat photo to drop a link to on the faecbook and see if the cluster needs a fan or anything.

What you think?
Grumpy old man.
Ex-G0KAP - I'd rather be doing it than talking about it.
"When found, make a note of." - Captain Cuttle

ejolson
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Joined: Tue Mar 18, 2014 11:47 am

Re: webserver clustering

Wed Oct 24, 2018 12:38 am

billybangleballs wrote:
Sun Oct 21, 2018 6:31 pm
What you think?
It is unclear whether you are trying to improve performance or reduce electrical usage. A go-faster stripe on the case sounds nice.

What sort of web application runs on 4 Pi computers and doesn't already saturate a 20 mbit connection?

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billybangleballs
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Re: webserver clustering

Wed Oct 24, 2018 7:33 am

It serves static webpages and my concern is not overloading the psu which is only rated at 10 amps. What colour do you think it should be?
Grumpy old man.
Ex-G0KAP - I'd rather be doing it than talking about it.
"When found, make a note of." - Captain Cuttle

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DarkPlatinum
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Re: webserver clustering

Wed Oct 24, 2018 9:32 am

You could use 5 RPi2 at 2 amps each. My RPi 2 can still work at 1 amp though.
1 * Raspberry Pi Zero W, 1 * Raspberry Pi 2, 1 * Raspberry Pi 3 1 * Raspberry Pi 3B + :mrgreen:

Check Out My Raspberry Site (Run on a Raspberry Pi 3B :) ): https://html.dynu.net

ejolson
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Joined: Tue Mar 18, 2014 11:47 am

Re: webserver clustering

Wed Oct 24, 2018 5:22 pm

billybangleballs wrote:
Wed Oct 24, 2018 7:33 am
It serves static webpages and my concern is not overloading the psu which is only rated at 10 amps. What colour do you think it should be?
I've been told that red means stop, green means go and yellow means go faster, so maybe yellow.

Since a single Pi computer should be able to serve static webpages at about 80 mbits, I don't see the advantage of adding more to the current setup when the upstream link is only 20 mbits.

Have you thought about hosting a text-based multi-user dungeon lpMUD game? Those can use plenty of CPU without needing much network bandwidth.

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billybangleballs
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Re: webserver clustering

Wed Oct 24, 2018 5:30 pm

I shall certainly bear it in mind once I get the case resprayed.
The multitude of Pi also gives me redundancy, as 3 can die and I'm still serving pages.
Obviously this just moves the single point of failure upstream from the Pi, but it's been an interesting project, and there's far more flashing leds to look at when you have a rig like this.
Grumpy old man.
Ex-G0KAP - I'd rather be doing it than talking about it.
"When found, make a note of." - Captain Cuttle

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DarkPlatinum
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Re: webserver clustering

Wed Oct 24, 2018 5:47 pm

billybangleballs wrote:
Wed Oct 24, 2018 5:30 pm
I shall certainly bear it in mind once I get the case resprayed.
The multitude of Pi also gives me redundancy, as 3 can die and I'm still serving pages.
Obviously this just moves the single point of failure upstream from the Pi, but it's been an interesting project, and there's far more flashing leds to look at when you have a rig like this.
Lifetime of a pi is 10yrs+... unless short circuit.
1 * Raspberry Pi Zero W, 1 * Raspberry Pi 2, 1 * Raspberry Pi 3 1 * Raspberry Pi 3B + :mrgreen:

Check Out My Raspberry Site (Run on a Raspberry Pi 3B :) ): https://html.dynu.net

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billybangleballs
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Re: webserver clustering

Wed Oct 24, 2018 9:00 pm

In that case, I shall endeavour to avoid short circuits, by using non-metallic paint for my go-faster stripe.
Grumpy old man.
Ex-G0KAP - I'd rather be doing it than talking about it.
"When found, make a note of." - Captain Cuttle

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DarkPlatinum
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Re: webserver clustering

Wed Oct 24, 2018 10:07 pm

billybangleballs wrote:
Wed Oct 24, 2018 9:00 pm
In that case, I shall endeavour to avoid short circuits, by using non-metallic paint for my go-faster stripe.
Lol go ahead and do that. Make sure the paint has adequate cooling when overclocked ;)
1 * Raspberry Pi Zero W, 1 * Raspberry Pi 2, 1 * Raspberry Pi 3 1 * Raspberry Pi 3B + :mrgreen:

Check Out My Raspberry Site (Run on a Raspberry Pi 3B :) ): https://html.dynu.net

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