Arg: no mdadm on Ubuntu 18.04.5 Desktop install disk?

[Robert Heller]

At Sat, 2 Jan 2021 21:16:17 +0000 "Ubuntu user technical support,  not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:

> 
> Hi Robert,
> 
> On Sat, 2021-01-02 at 16:04 -0500, Robert Heller wrote:
> > Arg! I want to install Ubuntu 18.04.5 on a LVM volume in the LVM
> > container on
> > my *existing* CentOS 6.10 system. The LVM container is on a software
> > RAID disk
> > (simple mirror set). This *appears* not to be possible (?) since the
> > Ubuntu
> > installer is not starting/seeing the RAID array and in live mode,
> > mdadm
> > appears absent (question: what happens if I try to run apt-get
> > install mdadm
> > on a live ISO system?).
> 
> It's not on the 20.04 live disk either as I just discovered. You can
> install mdadm with the above command on the live ISO system, manually
> assemble the disk array and proceed to the install. The installer
> should see the logical volumes then.
> 
> TBH, I've not tried installing to a raid array. I have a single ssd for
> the system and 2 spinning disks in a raid1 mdadm configuration. But
> I've done the above when I'ved needed to do an off-line fsck of my home
> volume.
> 
> > WTF? Does Ubuntu 18.04 in fact not support software RAID during
> > installation?
> 
> Not OOTB by the looks of things.

A serious flaw in my opinion....

> 
> > How am I supposed to procede?
> 
> See above.

Just that it seems seriously kludgy.  Wondering if I am going to have to 
create and have on hand a *custom* crafted "rescue" image -- eg a version of 
the Ubuntu installer disk with the software RAID modules and tools installed.

Of course I'll have to manually set up the network as well, since the box I am 
installing on is also normally the DHCP server for the network.

I never had this issue with CentOS 4, 5, or 6 -- all of *their* installer
disks included the software RAID tools on the installer ISOs (and 
automatically started the RAID arrays on boot).

> 
> Hope this is of some help.
> 
> Regards,
> Tony.

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