What to choose LVM or mdadm for organizing disk space on the server or is it hardware?

Question

linux

There is an old server with two hardware RAID controllers.
One controller is connected via PCI and allows you to connect 4 SATA screws.
The second controller is built-in for SCSI hard drives.
I tried to create three RAID arrays from them, and roll onto one of them (these are two disks in RAID 1), Debian with LVM, but in this case, RAID does not work for me or I somehow do it wrong :( Besides when installing Debian, I see all six screws and I don’t see raids, apparently LVM perceives raid arrays somehow differently :)
As a result, I thought about a hardware raid, but I don’t know how to organize it premium :( space could be managed on the fly and snapshot :)
How would you implement the configuration in this case?

Answer 1

If linux sees separate screws - this is a soft trade. And on softtrade, pooh - all the same, mdadm will actually be used. It is for this reason that, by the way, vmware does not see softtrades point-blank.
Hardware raid "outside" gives the array, and not a separate set of disks - it drives the disks itself.
I would buy an adapter and hook everything up to it.

Answer 2

A hardware raid is fraught with trouble. When a raid controller breaks down, you start running around with big eyes to find the same one. But if you have a soft-raid, then you simply raise the system with the same settings, stick disks and everything works for you.