Docker mirroring is how to achieve incremental modifications and maintenance?
Each mirror configuration consists of many levels, Docker Union FS used to incorporate these into the various layers to a mirror.
Typically Union FS has two purposes, one can not be achieved by LVM, RAID disk linked to a plurality of the same directory, another more common is a read-only to writable branch and a branch of the joint together, Live CD is based on this method can allow the user to allow some write operations on the basis of the same image on.
Docker built on AUFS vessel also uses a similar principle.