[CentOS] Intel RST RAID 1, partition tables and UUIDs

Mon Nov 16 23:10:00 UTC 2020
H <agents at meddatainc.com>

On 11/16/2020 03:36 PM, John Pierce wrote:
> the main advantage I know of for bios fake-raid is that the bios can boot
> off either of the two mirrored boot devices.    usually if the sata0 device
> has failed, the BIOS isn't smart enough to boot from sata1
> the only other reason is if you're running MS Windows desktop which can't
> do mirroring on its own
> On Mon, Nov 16, 2020 at 10:23 AM Jonathan Billings <billings at negate.org>
> wrote:
>> On Sun, Nov 15, 2020 at 07:49:09PM -0500, H wrote:
>>> I have been having some problems with hardware RAID 1 on the
>>> motherboard that I am running CentOS 7 on. After a BIOS upgrade of
>>> the system, I lost the RAID 1 setup and was no longer able to boot
>>> the system.
>> The Intel RST RAID (aka Intel Matrix RAID) is also known as a
>> fakeraid.  It isn't a hardware RAID, but instead a software RAID that
>> has a fancy BIOS interface.  I believe that the mdadm tool can examine
>> the RAID settings, and you can look at /proc/mdstat to see its status,
>> although from what I remember from previous posts, it's better to just
>> let the BIOS think it's a JBOD and use the linux software RAID tools
>> directly.
>> --
>> Jonathan Billings <billings at negate.org>
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Thank you. As I mentioned, I am running from one disk but and the two disks have identical disk UUIDs, identical partition UUIDs, both of which I assume is an effect of the BIOS fake RAID.

If I were to go with Linux mdadm and a RAID 1 configuration, am I correct in assuming that I would:

- decide which one is the "master" disk

- configure mdadm to sync to the other disk

Would I need to change disk UUIDs, partition UUIDs on the second disk prior to this or mdadm would synchronize as needed?