→Stacked images: rephrasing
== Stacked images ==
you do [[incremental dumps]] there appear the <code>parent</code> symlink and images with pages become dependant on each other.
There appears the 3rd field in the pagemap, called <code>in_parent</code>.
When set this boolean value means , that the respective data for the pagemap should be found in the parent images. While searching for data in parent the same algorithm is used -- first the pagemap is resolved, then the data is found in pages. For parent images, the data (either complete or partial) can also be found in ''its'' parent images.
=== Example ===
In this case the pages image would be only 32k in size, since the first 4 pages
should be found in the parent. Thus the parent pagemap image should container one ore more pagemaps that cover the <code>0x1000000 ... 0x1004000</code> area, for example like this
This, in turn,
would mean that first 2 pages from this range are in parent 's pages image file and the last 2 should be looked up deeper -- in the grand-parent pagemaps.
== Deduplication ==