The green led (ACT) on my Raspberry Pi 3 is set to
mmc0 to flash on SD card activity via
echo mmc0 |sudo tee /sys/class/leds/led0/trigger
However, it flashes much more often (randomly every few seconds) than it should according to
iotop -bktoqqq -d .5
iostat -dzp 5
So I wonder what is the light indicating if nothing is read or written to the SD card for many seconds or minutes.
Has anybody seen this LED off for longer periods in the
mmc0 mode or does it always flash unrelated to SD card I/O on a Raspberry Pi 3?
It also has an
mmc1 mode, in which it flashes even more frequently. I wonder what that indicates.
Why does it matter? After a colleague pointed out that Raspberries kill SD cards, I wanted to reduce my writes to my SD card in order to increase its lifetime and was expecting a less flashing LED indicating some sort of success. Now I am worried that the controller is still messing with it.