Re: Read-only FS, switch-off safety for raspberry pi

[Jason Thorpe <thorpej%me.com@localhost>]

> On May 17, 2019, at 12:20 AM, Sad Clouds <cryintothebluesky%gmail.com@localhost> wrote:
> 
> Sound like too much hassle for very little gain. I use and abuse all
> sorts of SD cards on various devices and never had any I/O errors.
> Although I don't buy cheap rubbish brands that nobody ever heard of,
> most of my cards are SanDisk. Keep back ups of your data and if
> anything goes wrong, just replace the card.

There are other reasons for doing this.

I have a not-yet-completed (still in breadboard phase because there's a bunch of PCB layout I haven't done yet) project that uses a RPI running NetBSD as the system controller, and I'm mostly concerned about any-time-unplugability and fully headless operation (you'd have to take the thing apart to access the console UART header).  All of the config files that can possibly be changed at run-time are on a msdos partition normally mounted ro, but temporarily upgraded to rw,sync when the user changes some configuration option (a very rare operation), and then downgraded back to ro, and symlinks from the FFS partition (always mounted ro) point info the msdos partition.

In my case, I want the thing to be fully up-and-running within a few seconds after being plugged in, and I don't ever want to have to field a call saying "hey, that thing you gave me isn't working" and have the problem be "the file system is curdled".

-- thorpej