Get a cup, this will be long.
Its the weekend, I have all the stuff I need for setting up and getting ready for development of the prototype. I decide the first thing to do is install the OS on the new Pi's. Little did I know, a simple process the first time would end up taking almost 2 days.
I picked up 2 micro SD cards, for dirt cheep, they were the proper spec, but as you will see, not all cards are the same. One of the cards was 32 gig, the other was 128 gig. I wanted the 128 for my Pi as it would be the one I would use the most for development.
The idea was this machine would have a monitor and all the other Pi's would be headless and accessible with SSH and remote XWindows. Yes, I know, I know, the specifications say that only up to 32 gig. However, with a simple hack that I learned you can use higher density cards. If you like, you can read about it here. https://www.webtechgadgetry.com/how-to-format-larger-sd-cards-for-raspberry-pi/
I know off track again. Hold on, let me get a drink.
I decide to install the first Pi with the 32 gig card, wanted to be sure that the larger drive did not cause me issue. As this was a blank sd card, I had the choice of installing the OS via an image, or installing noobs on the SD card and installing the OS from noobs.
I decided to use NOOBS. I download, unzip it, copy the files to the micro SD card. it seems fast and soon the 1 gig of files is ready for me to boot the Pi off of.
I boot, and am greeted with the NOOBS instal screen, as expected. I start the install, and I notice the install is taking much longer then the first Pi. The write speed is showing at under 500k per sec, and it needs to install 3 gig. Something is wrong, time to research.
I did let the install complete while I looked into it. When the machine finally did boot, it was unusable, it would lock up, then unlock. It was like being on an old time BBS at 300 baud. Giving my age away.
It seems that 4k writes is the write size the OS uses, as such you need to find cards that are fast at that block size. Some good information as well as a benchmark script can be found here. http://www.pidramble.com/wiki/benchmarks/microsd-cards. Please be aware that using the benchmark will trash the micro sd card and all contents will be lost.
So what I learned is the cards I had bought would not work in the Pi. As such I went back out the next day to find cards that would work. I simply went on recommendations, as well as testing the card in the store before I left. Yes, I had a Linux based laptop with me.
After finding acceptable cards I went home and installed the 32 gig card in one of the Pi's and the write speed was perfect.
What you should learn from my mistake. Make sure you get the proper micro SD card. Its the single most important choice you can make. No, you don't have to spend a ton of money to get the speed you need. I got both cards for well under 100 USD.
In case anyone is wondering, yes I was able to properly format and use the 128 GIG memory card in the Pi. Its nice to have extra room for growth.
Next up, development environment.
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