On Sun, Dec 02, 2018 at 12:06:03PM +0100, info at smallinnovations dot nl wrote:
> On 02-12-18 11:41, Edward Bartolo wrote:
> > The purpose of this email is to ask how to radically minimized write
> > cycles to the SD CARD when I run Devuan for Raspberry Pi 3. I found a
> > how-to which uses /tmp fs for frequently modified system files, but
> > the user uses systemd and I do not want to have that.

> One dramatically sdcard saving option is to use noatime when mounting
> your sdcard in /etc/fstab like
>
> /dev/mmcblk0p2 / ext4 defaults,noatime 0 0

Keeping the very concept of atime is _sabotage_. It was one of the ideas
made when the world was young and when I/O was cheap compared to other
performance-related components. You'd want to set noatime on every machine
you control.

Especially on:
* media with limited write cycles (<- you are here)
* thin storage
* CoW disk images
* filesystems with snapshots
* read caching

> It disables writing a timestamp when a file or directory has been
> accessed. Other options i know of are using JFFS2 made for flash kind of
> storage.

These days, I'd recommend f2fs -- much newer, faster, and doesn't differ
from a regular filesystem from a naive user's point of view. And staying
naive saves your time.

> Using aufs or unionfs which in fact create a readonly fs with
> changes in RAM which can be write back to disk when your system shutdown
> in a orderly fashion.

Pretty risky, and requires non-negligible human effort.


Meow!
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