Raspberry Pi write cycles

Alexander Schreiber als at thangorodrim.ch
Wed Aug 14 16:36:24 CDT 2019

On Fri, Aug 09, 2019 at 02:43:38PM -0700, Adam Thornton via cctalk wrote:
> I did have a case where the Pi I was using as secondary DNS/DHCP and as the
> secondary backup server (using USB spinning disk) destroyed its SD card.
> But then it turned out not to be the load at all.  No matter what I ran on
> that Pi, it would corrupt its SD cards in a matter of weeks (the symptom
> was that the fourth bit of some bytes would just stick on).  I assume it
> was just something broken in the Pi itself.

The two usual suspects:
 - standard consumer sd cards don't do so well outside of their design
   use case (mostly cameras and media players) and I suspect a journaling FS
   (which is a perfectly reasonable default, usually ext4 these days,
    for Linux) is probably especially bad - so I recommend looking for
   industrial grade SD cards, they cost a little more, are usually only
   available in smaller sizes (I've seen 8, 16, 32 GB) but they tend to
   last a lot longer
 - sub-par power supply, having the power brown out a little is _bad_
   for basically any kind of reliable operation - make sure your PSU
   can actually reliably deliver enough juice (ISTR the recommendation being
   3+ amps), I suppose the "official" ones from the Pi foundation should
   be up to the job

> (Traffic encryption via simh is incredibly painful.  You have to turn login
> delay waaaaay up to run NetBSD on VAX on a Pi if you want to be able to ssh
> into it; the machine itself runs fine-ish, but the zillions of cycles to
> encrypt the traffic swamps it in no time.)

If you want to stick with the Raspberry Pi platform, what kind of Pi are
you currently using? If it is a Pi 3, maybe try a Pi 4, that is noticeably
beefier. Note: with the Pi 4, you have to use the official power supply
and cable as they screwed up the USB-C side (by _not_ exactly copying the
schematic in the specs, saving one resistor on the BOM with the result that
high end cables will mis-recognize the Pi as an 'audio accessory' and not
power it).

> And, you know, if you manage to cause my SD cards in those machines to
> fail, well, gosh, guess I'm out $10 or so for a new one.  I'm not bothering
> to back up any of the stuff inside 'em,

I assume you've got a master image that you just write to a new SD card,
replace card, power cycle Pi, done?

Kind regards,
"Opportunity is missed by most people because it is dressed in overalls and
 looks like work."                                      -- Thomas A. Edison

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