As far as I know, only the OS is installed in the memory, and only the plugin installation can be registered with the SD card.
Even if the SD card is unmounted, there will be no problem as the OS and basic functions are stored in the internal storage.
What I want is a way to check the storage capacity and automatically save to SD card when installing additional individual installation packages.
In the storage of Luci or Mifi, only the main storage is displayed, and the capacity of the SD card is not displayed.