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Comment by wybiral | Hacker News Reader

You better have some good redundancy on those SD cards because I've run Pi clusters before and most of those cards go corrupt pretty quickly with any frequent number of writes.

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It's possible to netboot too[1] but there are other practices for saving write-wear on cheaper flash (read only partitions/overlays and seperate log partions in mem etc)

[1] https://www.raspberrypi.org/documentation/hardware/raspberry...

after boot, the sd cards for my pis go into readonly :) checkout cattlepi.com on how this is done. i’ve had good luck with the lifetime of the cards, but it’s also true I treat the Pis as disposable.

I started building "real" firmware for my raspi appliances using buildroot. That makes it super easy to build images that completely run from initramfs without a single write on the sd card (and are fully booted in a few seconds including userland).

Only works if I don't need any local persistence but makes the Pi just work super reliably. Upgrading is as easy as swapping the Linux Kernel image on the fat32 and rebooting.

cattlepi has the advantage of being able to essentially build and distribute images over the network + full raspbian.

on boot it self-updates if needed, builds on overlay filesystem w/ the squashed image as the bottom ro layer + tmpfs as top rw layer.

Thanks, cattlepi looks super interesting!

So you're storing data in an external drive?

2 scenarios: one is to run the app and push metrics and logs in real time. the other is to use external storage (a drive, nas or directly w/ the cloud like for eg S3)

That might be actually a good thing. Any disk will break. If disk breaks sooner, you'll have to have a good recover plan and not just hope that this RAID-1 will save you, because probability is not that high.

It's more in annoying rather than good territory. Spam the generic cards with enough writes and you'll be able to corrupt many of them within days. If you do write-heavy things or expect reliability from your rpi, you pretty much have to use an external drive. And hopefully some log/journal based filesystem.

One partial fix is to vastly over provision SD card storage. SD cards use very simple wear leveling algorithms, so having a card that is 20X larger than necessary can extend life a lot.

Or buy high-endurance SD cards that are _designed_ for heavy/frequent writes instead of the cheapest thing on ebay.

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