I have set up a local server with an old laptop so I was using RAID 1 mirroring for reliability= 2* 1TB HD SATA 2.5". I did use the Intel RST built in functionality. Only Ubuntu Desktop version recognized the Intel RAID configuration (I don't know why the server version didn't).
Anyway, while mounting back again everything after the first setup, unluckily a cable didn't get connected properly. Everything was running flawlessly, but the day after I've realized that 1 HD was disconnected. So I shut down and replug correctly the HD.
At the reboot, the RAID boot screen flags RAID with "REBUILD". I enter the utility and it tells me I need to rebuild the RAID from the operating system. Also the boot time was incredibly longer than usual. I followed these steps, from the last messages: configure mdadm for existing intel rapid storage array
sudo dmraid -s told me the raid had 2 devices.
sudo dmraid -r told me the RAID had 2 HD with the same blocks. From here everything seemed working properly.
So I tried anyway to rebuild with "sudo dmraid -R [raid set]" to get rid of the "rebuild" flag. After I've done this, 1 HD wasn't recognized anymore from Ubuntu. So I decided to reboot...and voilà: RAID is not recognized anymore, system doesn't boot at all with none of the HDs.
What do you suggest to do? Shall I format and start from scratch? Is there a way to rebuild the RAID without formatting? For the future: how to rebuild safely in ubuntu?
THank you all and sorry for the long post
PS why ubuntu server doesn't recognize the Intel RAID?
"mdadm Linux software raid is far better tested and supported. You will have much fewer problems with it, and it also will resync much faster when you plug the missing drive back in, so you should use that instead of dmraid. It also can do things like add a third disk later on if you want, which you can not do with the fake raid stuff."
I guess I should avoid using dmraid?
– user3303102 Jun 14 '21 at 13:09