zephyr Settings backend options understanding

[Ibrahim_Augury]

Hey
I see that there is three options for saving the settings 
Zephyr has three storage backends: a Flash Circular Buffer

(:kconfig:option:`CONFIG_SETTINGS_FCB`), a file in the filesystem

(:kconfig:option:`CONFIG_SETTINGS_FILE`), or non-volatile storage

(:kconfig:option:`CONFIG_SETTINGS_NVS`).

Trying to understand the best option for me 
Where can I find more info about every one of them what are the differences between them if I am using my external flash for saving the settings ?

Thasnk a lot ...

 

[Kenneth]

Hello,

Check out:
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/services/storage/index.html

The NVS is the recommended option (this is also stated when reading for instance documentation for FCB).

Kenneth

[Ibrahim_Augury]

on my coustom board I have an external flash memory .... I am already using the  

CONFIG_FILE_SYSTEM=y

CONFIG_FILE_SYSTEM_LITTLEFS=y
Can this be a problem 
As I saw in the flash_map_pm.h file 

#if (CONFIG_SETTINGS_FCB || CONFIG_SETTINGS_NVS || defined(PM_SETTINGS_STORAGE_ID))

#define storage settings_storage

#define storage_partition settings_storage

#elif CONFIG_FILE_SYSTEM_LITTLEFS

#define storage littlefs_storage

#define storage_partition littlefs_storage

#elif CONFIG_NVS

#define storage nvs_storage

#define storage_partition nvs_storage

#endif
One will be chosen 
also I want to use the settings for saving the ble pairing keys and info ....  

[Kenneth]

Hello,

After building the project you can open the following two files to see what was used:

<build>/zephyr/zephyr.dts

<build>/zephyr/.config

You can then change settings as you see fit in your .overlay or prj.conf file.