I repost here the 39th comment, which gives a possible explanation of the issue:
Storm in a teacup
Date: 2016-09-22 09:17 am (UTC)
From: [personal profile] cowbutt
"Intel have not submitted any patches to Linux to support the "RAID" mode."
Such patches are unnecessary, as mdadm already supports Intel Rapid Storage Technology (RST - http://www.intel.co.uk/content/www/uk/en/architecture-and-te... ) for simple RAID (e.g. levels 0, 1, 10) arrays, allowing them to be assembled as md or dmraid devices under Linux.
However, it would appear that the version of mdadm in shipping versions of Ubuntu (at least - maybe other distros too) doesn't support the Smart Response Technology (SRT - http://www.intel.com/content/www/us/en/architecture-and-tech... ) feature that's a part of RST and is used by Lenovo to build a hybrid one-stripe RAID0 device from the HDD with a cache on the SSD (I'm sure Lenovo have a good reason for not using a SSHD). Dan Williams of Intel submitted a series of patches to mdadm to support SRT back in April 2014: https://marc.info/?l=linux-raid&r=1&b=201404&w=2 . Perhaps now there's shipping hardware that requires them, there'll be the impetus for distro vendors to get them integrated into mdadm, and their auto-detection in their installers to use the functionality provided sanely.
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I should add that mdadm is not present in Ubuntu live images by default - one has to pull it in by issuing "sudo apt[-get] install mdadm". BTW, I don't know if mdadm would detect the RAID controller/disk immediately upon installation, or it would require a reboot. In the latter case you may wish to use a USB key with enough spare room to save the system status and reboot. I'd use UNetBootin to prepare such a USB key.
The main issue here is, a user who doesn't even see a disk, probably wouldn't know to go as far as installing mdadm.
IMHO, given the broadening diffusion of NVMe and RAID devices, Debian, Canonical, REDHAT, Fedora etc. might wish to make mdadm part of their live images by default (and eventually strip it from the installed system if it's unnecessary).
Such patches are unnecessary, as mdadm already supports Intel Rapid Storage Technology (RST - http://www.intel.co.uk/content/www/uk/en/architecture-and-te... ) for simple RAID (e.g. levels 0, 1, 10) arrays, allowing them to be assembled as md or dmraid devices under Linux.
However, it would appear that the version of mdadm in shipping versions of Ubuntu (at least - maybe other distros too) doesn't support the Smart Response Technology (SRT - http://www.intel.com/content/www/us/en/architecture-and-tech... ) feature that's a part of RST and is used by Lenovo to build a hybrid one-stripe RAID0 device from the HDD with a cache on the SSD (I'm sure Lenovo have a good reason for not using a SSHD). Dan Williams of Intel submitted a series of patches to mdadm to support SRT back in April 2014: https://marc.info/?l=linux-raid&r=1&b=201404&w=2 . Perhaps now there's shipping hardware that requires them, there'll be the impetus for distro vendors to get them integrated into mdadm, and their auto-detection in their installers to use the functionality provided sanely.
---
I should add that mdadm is not present in Ubuntu live images by default - one has to pull it in by issuing "sudo apt[-get] install mdadm". BTW, I don't know if mdadm would detect the RAID controller/disk immediately upon installation, or it would require a reboot. In the latter case you may wish to use a USB key with enough spare room to save the system status and reboot. I'd use UNetBootin to prepare such a USB key.
The main issue here is, a user who doesn't even see a disk, probably wouldn't know to go as far as installing mdadm. IMHO, given the broadening diffusion of NVMe and RAID devices, Debian, Canonical, REDHAT, Fedora etc. might wish to make mdadm part of their live images by default (and eventually strip it from the installed system if it's unnecessary).
Edit: clarified