[Feature Request] [RoF] Ubuntu Desktop - Inclusion of RAID

[n1v0la]

Observations:
- RAID is no longer only of interest to Server users
- It appears that a number of users would like to use RAID on desktop machines (see also previous bug reports on missing RAID)
- Forums, web sites, tutorials about RAID with Ubuntu Desktop seems to consist to a large part of explanations, how to get actually get mdadm
- Getting mdadm onto an Ubuntu machine without Internet connection during installation appears to be a bit tedious

Since the RAID feature issue has been open for some time, and there seem to be lack of resource to address it, may I propose breaking down the task as follows:

Step/Phase 1: Inclusion of mdadm in Ubuntu Desktop releases (same as for Ubuntu Server)
 This would allow users to boot a Live CD and use CLI to manually set-up/configure RAID, and then run Ubiquity installation
 Result: Including mdadm would get rid of the apt install step and the requirement for Internet connection, while and also simplify documentation/tutorials for workaround(s)
 Target date: Maybe 21.04 release

Step/Phase 2: Add a CLI to Ubiquity (e.g. could show up when selecting manual disk partitioning)
 This would allow users to manually set-up/configure RAID from within Ubiquity
 Result: The user would not need to boot a Live CD evaluation before running Ubiquity
 Target date: Maybe 21.10 release

Step/Phase 3: Include RAID support in Ubiquity
 Full RAID support in Ubiquity, which would probably make use of mdadm.
 Result: RAID Feature as requested by several users over several years
 Target date: Maybe 22.04 release

Ref: Ubuntu Development Discussion <email address hidden>
  "[Feature Request] [RoF] Ubuntu Desktop - Inclusion of mdadm for RAID"