Kubuntu alongside Windows 10 on Intel's RST RAID O array

[Caesar]

Hello!

I will try to explain my problem as simply and shortly, as I can.
1. I have a gaming laptop - GT75 Titan 8RG
2. It has an Intel CM246 chipset and M.2 SSD Combo (NVMe PCIe Gen3/SATA) with two Samsung SSD drives PM961 MZVLW256HEHP combined together into a firmware RAID 0 array – specification on the screen below

3. I divided this RAID 0 array into two equal partitions and installed Windows 10 Pro 64 bit on one of it – without any problems
4. The other partition is meant for Kubuntu 19.04., but sadly I cannot make it to see the array, and that’s the part in which I need help

I did some reading on RAID volumes under Linux, I tried to get a little bit inside Intel Rapid Storage Technology (Intel RST) in Linux document, and mdadm manual, but obviously I lack the know-how. Kubuntu doesn't detect the array, it even doesn't detect the SSD drives which are its components – lsblk command does not reveal them (in the picture: sda is my 1TB HDD, and sdb is an USB flash drive from which I run Kubuntu Live),

but lspci | grep RAID shows that my system has RAID configured.


But mdadm seems not aware of my array...


Is there a way I could install Kubuntu 19.04. alongside Windows 10 on my RAID array without destroying Windows installation? Many people on the Internet advised others to assemble a RAID array with mdadm, but my array is already assembled and I don’t want it to be destroyed.

[oshunluvr]

AFAIK, there is no support for Intel RST in Linux. I just ran into this with my new laptop. It had RST enabled on a single drive laptop for some unknown reason.

Bottom line is Linux does not detect RST drives. If you want to run Linux on that PC, either add a second drive or backup your stuff and remove the RST RAID. Hardware RAID is a horrible idea anyway.

[claydoh]

AFAIK, there is no support for Intel RST in Linux. I just ran into this with my new laptop. It had RST enabled on a single drive laptop for some unknown reason.

Bottom line is Linux does not detect RST drives. If you want to run Linux on that PC, either add a second drive or backup your stuff and remove the RST RAID. Hardware RAID is a horrible idea anyway.

lenovo or a thinkpad, I imagine?
I had an issue with RST on my Lenovo laptop, but nothing to do with Linux support. My spinning HDD was using RST by default, and the installer saw it just fine, but the nvme SSD would not be detected by the system at all, even in Windows, until I figured out tio disable RST. I still haven't figured out why they have it set up this way.

[Caesar]

Well, according to Intel RST IS supported under Linux with mdraid or dmraid (deprecated). It all is described the document mentioned in my first post (Intel Rapid Storage Technology (Intel RST) in Linux). Intel also states in his document, that RST is supported out-of-the-box in Novell SLES and Red Hat, but I don't have access to any of this.

[Snowhog]

Maybe review this thread over on ubuntuforums.org?

[Caesar]

Well, one advice seems to be repeating on many places - change setting in SATA Mode from RAID/RST to AHCI. It's not something I was looking for, but did that just to test if Kubuntu installer sees my SSD drives



and now





But still "mdadm --assemble --scan" does nothing - this time it retrieves no information.
Anyway, it's not the way I want it to be, as I will most surely lose my Windows 10 installation and of course no RST.

P.S. Still working on it. It seems Kubuntu is detecting RAID, but lacks a driver...

[oshunluvr]

lenovo or a thinkpad, I imagine?
I had an issue with RST on my Lenovo laptop, but nothing to do with Linux support. My spinning HDD was using RST by default, and the installer saw it just fine, but the nvme SSD would not be detected by the system at all, even in Windows, until I figured out tio disable RST. I still haven't figured out why they have it set up this way.

Yes Lenovo laptop and same sort of experience. In my case it was a single factory nVME SSD that had RST enabled. All that I've read (not a terribly large amount, but I did 4 hours or so of 'net research) says there's no advantage to enabling RST in a single drive environment.

What I did was to boot to windows, boot to BIOS and disable RST there, reboot Windows into safe mode, enable the Microsoft driver in place of the Intel RST driver, reboot. Worked fine. It was brand new so I had nothing to lose except Windows anyway and I could have reinstalled it. After this, Linux was able to address the SSD so I shrunk the windows partition and set up Linux.

[oshunluvr]

Well, according to Intel RST IS supported under Linux with mdraid or dmraid (deprecated). It all is described the document mentioned in my first post (Intel Rapid Storage Technology (Intel RST) in Linux). Intel also states in his document, that RST is supported out-of-the-box in Novell SLES and Red Hat, but I don't have access to any of this.

Not trying to argue but that document is from 2011 and I personally would never rely on any Linux info that old. Everything thing I've read says those who have tried to enable RST support on free Linux distros have failed or ended up destroying their arrays. But hey, I honestly wish you luck. Please, if you find a solution that doesn't trash your array, post it here because I'm sure others will want to know.

Again, just my opinion - but as a fairly heavy RAID user (think "enthusiast") for almost 20 years I would never advise using any form of hardware RAID unless you have multiple hardware device backups, and I refuse to work on them. Here the logic behind my belief:

There is no tangible benefit to hardware RAID - as in vastly greater performance - and the RAID devices are not widely transportable - as in easily moved to another computer for access. If your RAID controller or motherboard dies, you have to have an exact replacement or a 100%-ish compatible one. The only thing in the computer world that changes faster than the Linux OS is hardware like mobo's. You've got a 6-8 month window before you can no longer get an exact replacement so you end up banking on backward compatibility. Fine, if you're 100% confident in your backup strategy and don't mind the time investment. However, Intel RST will likely be around for a while longer than the older mobo RAIDs were. On the other hand, MDADM or BTRFS RAID are easily transportable to nearly any distro. Unlike hardware, older Linux releases are widely available for years after they've stopped being updated and the developers have an interest in maintaining backward compatibility.

The only reason I can come up with to use hardware RAID is if you intend to dual-boot and use both OSs regularly enough to benefit from RAID in both environments. No one I know can make that case with any real veracity. Simply sharing drive space isn't much of a benefit. Frankly, with modern drive interface speeds the drive I/O bottleneck is much less of a problem.

Good luck with your attempt though, do let us know how it goes.

[oshunluvr]

I will say I've found blogs/posts that talk about creating mdadm RAID with Intel RST support, but that is vastly different than mounting an existing array. For example, when creating an RST array under mdadm, you must create the container using imsm metadata. Maybe that's the piece you're missing?

[Caesar]

I will say I've found blogs/posts that talk about creating mdadm RAID with Intel RST support, but that is vastly different than mounting an existing array. For example, when creating an RST array under mdadm, you must create the container using imsm metadata. Maybe that's the piece you're missing?

Yes, I knew that already. Well, as Windows 10 will soon have it's major Spring Update I intend to do a fresh install (updating with previous October 2018 update gave many people major "headaches"), so creating an new array won't be problem, but still I want RST, so the major issue is how to make Linux see it?

According to this



My chipset - Intel CM246 - is supported from kernel 4.14, but not RST?

[Caesar]

Anyone?

Well, I still haven't found an answer, but this is what I've run into when searching through WWW

Linux*
Beginning with Linux* kernel version 2.6.18*, the dmraid* utility 1.0.0-rc15 supports RAID 0, RAID 1, and RAID 10.
Beginning with Linux kernel version 2.6.27*, the mdadm* utility 3.0 supports RAID 0, RAID 1, RAID 10, and RAID 5.
The kernel provides the RAID level support. The utilities support the Intel® Matrix Storage Manager metadata format.

To use the RAID features in dmraid and mdadm, set up the RAID volume using the Intel Matrix Storage Manager option ROM. To enter the option ROM user interface, click CTRL+I when prompted during boot.

Instructions on how to use the RAID features in dmraid and mdadm are included with Linux. This information is provided as a courtesy by Intel. Contact your Linux vendor for additional questions and support.

Still I'm not sure what I'm doing wrong. Is it possible that distros like Kubuntu or Manjaro just don't have RST option compiled in their kernels?

[Caesar]

Well, unfortunately I wasn't able to make Kubuntu (or other distro) see my Intel RST RAID 0 array, so I dismantled it. In case someone has any doubts that RST gives some extra performance (I've read posts nearly saying that it is only pure evil), heres the comparison:

1. SSD test on Intel RST RAID 0 (fake RAID) on Windows 10


2. SSD test on single SAMSUNG MZVLW256 (NVMe PCIe Gen3 x4) on Windows 10


I hope that we will see RST support in Linux ASAP.