Flash memory durability (SPIFFS)

[esp1979]

Hello all,

i have a question to the durability of the flash memory:

Is it true that the flash memory of the ESP32 can slowly break after about 100000 write cycles?
And if yes: What exactly means "write cycles"?

Following example:

I want to save 300 measurings a day (e.g. temperature measurings) in a file.
For each day a new file is created named with the current date.

So e.g. for today i would have a file called "2021-01-10.bin"

If i then

open the file
append the new measuring by file.write
close the file

and do this 300 times.
Would that be 300 write cycles?

This would mean that i would have 109500 write cycles a year (300 * 365).
And that would mean, that the flash memory would be defective after about a year.
Is this correct?

Best wishes
Daniel


Thank you for your help and a good healthy new year to everybody!

Daniel

[esp1979]

Hi,

really no one that can help ;-(

Best wishes
Daniel

[ESP_Sprite]

Technically, it's 100000 erase cycles per sector, meaning that each (4K large) sector can only be erased up to that amount of times before a flash cell may break. The thing is that flash filesystems like spiffs will do wear leveling, in other words: every time you write a file, it will do that to a different (set of) sector(s). I am not intimately familiar with the workings of spiffs, so my numbers could be off, but as an indication: say you have a spiffs that is 1 megabyte in size, or 256 4K erase sectors. Assuming your file is small, and spiffs only needs to erase one sector per erase/create/write cycle, this means it can do this 100000 times for each erase sector, but it has 256 sectors to spread the load over, which means 25600000 times in total.

[esp1979]

OK, that sounds good.
Thank you for your detailed answer.

Best wishes
Daniel