Nand and rfs, ro, rw file system for application

In our current system we are using the following approach.

  1. We have a base rfs (on ro nand partition)

  2. We have a rw partition as well which is used to store persistence data.

  3. The final rfs is a squash file which is stored on the rw partition.

  4. On boot we create an overlayfs on which we mount the rfs squash

We wanted limit nand writes so we used the overlayfs, hence the rfs is a ro.

And any data is stored in the persistence partition.

Given mender we are thinking of a couple questions

  1. If we use mender A/B nand ubi partition (are A and B rw?) on this case the mender delta in delts rfs updates is directly applied on rw partition B.

  2. If we use the above how can we reduce nand writes or make A and B partition ro ?