Added a note about transactional systems

doc/storage_ui.md

@@ -10,6 +10,17 @@ and how they will interact. Something that is represented as a sentence in the s
 become a tool-tip, a given icon can become a label, actions grouped in a drop-down can end up
 being represented as separate buttons, etc.
 
+### Transactional Systems
+
+Agama is able to install transactional distributions like openSUSE MicroOS. There will be no option
+in the Agama storage user interface to set whether the root file system of the installed system
+should be transactional (also known as "immutable") or not. Since the implications go beyond the
+file system settings, the nature of the system (transactional vs read-write) will be determined by
+the selection of the operating system to install, "product" in Agama jargon.
+
+This document describes the Agama interface for a traditional (non-transactional) system. See the
+section "interface changes for transactional systems" for the alternative.
+
 ### Representation of the Actions to Perform
 
 Another important point to consider is that currently the list of (libstorage-ng) actions is the
@@ -231,6 +242,17 @@ Of course, at any point in time the user could modify the root volume and switch
 auto-calculated) limits. In that case, the entered values would be observed and would not be
 automatically recalculated anymore, despite any configuration for the default volumes.
 
+### Interface Changes for Transactional Systems
+
+As explained at the beginning of this document, Agama can install some transactional distributions.
+In those systems, it makes no sense to disable Btrfs snapshots, which are required to provide the
+functionality. Is not only that snapshots are mandatory in transactional systems, they are actually
+used with a different purpose when compared to read-write systems.
+
+Thus, if the system being installed is transactional, that will be clearly stated at the "settings"
+section of the storage proposal page. The setting to use btrfs snapshots will not be there and the
+root file system will be labeled as "transactional" in the corresponding table.
+
 ## Advanced Preparations
 
 As mentioned above, in addition to the page for defining the proposal, Agama will offer interfaces to