Whether a virtual cluster can substitute for a physical one depends on the focus.The 27w for a Pi 5 is for a heavily loaded pi, so to speak. A Pi 5 will run just fine on 3A. Make it 3.5a if we're going to hook it up to an USB keyboard and mouse, but you're still going to have a bit of power to spare.I have already looked at this........
Firstly you will need as many POE adapters as you have pi's
https://raspberry.piaustralia.com.au/pr ... pi-poe-hat (@ about 40 dollary do's each) NOTE. these must be designed for the RPi 5
Then you will need to buy a POE++ switch and this one is the best power budget wise and the best price.....
https://www.scorptec.com.au/product/net ... d_source=1 (585 dollary do's)
This switch has 4x 60W ports (which can power CCTV cams or wireless access points and 4x 30W ports with a total POE budget of 230W
Given that the power supply for the RPi 5 is 27W, you will be able to plug 8x RPi 5's into this switch and still have a little bit left over
I have already done this with RPi4's and have a 4 pi's with POE adapters plugged into a 4W switch
It's not a cheap way of doing things, but only having an ethernet cable going to the pi looks pretty cool
The POE hat is what I ended up with by the time I was done with my cluster. But I did not buy them all at once. Basically took me 7 months to get all of them their own poe hat, but the cluster started out with all pis communicating on wifi (their own,separate from the rest of our network).
Yes, it is slower that way,but won't cost an arm and a leg, especially because you can get some very beefy servers on eBay for a fraction of the cost and build a cluster out of vvms.
But I initially, all those pics were powered by an UPS like the one I linked to above. I even thought about sacrificial USB cables to power each by via the usb-c socket, but that was going to be more wasted money, so they all got 5v hardwired to the io header.
All in all, bag for the buck, a blade server from eBay is going to be a much better way to learn and play with clustering. Though if you already have a bunch of Pis or you aquire one or two heremand there over time, it is a fun project (and expensive), but no one ever complained of having too many Pis and one can always come up with something or other to do with every Pi board they have once the cluster project is done and you move on tho to other things.
For example, failure modes, communication latencies and memory bandwidth tend to be quite different between physical clusters and virtual ones.
My impression is the people building clusters with Pi computers are actually looking for the hardware characteristics of a physical cluster at an affordable price and energy budget. Usually the goal is not to build a fast machine but to do it yourself. Ideally the experience saves time and money later when setting up a more expensive cluster based on Xeon or EPYC processors.
There might even be cases where a cluster of Pi computers is practical.
Even better is when it's fun and practicality is not a consideration or requirement.
Statistics: Posted by ejolson — Sun Jan 21, 2024 8:07 am