Doubts about fstorage in sdk 16.0

[Yadhu KP]

Hello,

We are using nrf52832 with sdk 16.0, for a particular reason we are storing some variables in flash storage, i have some question regarding that 

1. what is the time for erasing, read and write cycle for flash storage?
2. it shows that 10 000 cycle is the endurance of flash if I write and erase a variable greater than that what will happen
3. Why is fstorage shown as experimental

expecting a fast response

[haakonsh]

1. Basically this Electrical specification. There is very little overhead of storage vs CPU read/write to flash. 

2. Most likely nothing, but eventually you'll have a few bits that are corrupted. Note that that is 10 000 erase cycles. Not how many times you write to a block. 

3.  fstorage is used by a lot of modules, there's simply not enough time to test every corner-case in our build tests, that's why we label it as experimental. We use it in almost every module that needs persistent storage and we consider it as production worthy for all normal use-cases. 

[Yadhu KP]

Thank you so much mr haakonsh for your answer, Is there any way to minimize this erase cycle, and write variable in to a page?

[haakonsh]

Yes, some basic flash wear leveling(https://en.wikipedia.org/wiki/Wear_leveling) will help a lot. 

The most basic routine is to always write sequentially to flash and never to the same address over and over again. Wait until you've filled a page before you erase it. Use as many pages as you can, and distribute the number of erase cycles across them. 

More advance usage is to run error-checking checksums on pages in order to identify pages with memory corruption and disable their use. You can also run error-correcting algorithms to extend the lifetime of a page instead of disabling it, alternatively blacklist certain memory addresses that are corrupt. 

[Yadhu KP]

Thanks, Mr haakonsh for this valuable information.