In this post we're going to explore using LVM to reduce the space needed by a dual rootfs setup. In a typical dual rootfs setup, the device needs to have two times the space needed by the rootfs partition, in order to have an inactive partition to stream a new update into. But in a typical patch update, not that much will have changed from what's already on the active partition. Perhaps a few libraries got a patch update, maybe some data files got an update, but most files will remain the same. What if we could take advantage of that?
This is a companion discussion topic for the original entry at https://mender.io/blog/using-lvm-to-reduce-dual-rootfs-footprint