New RAID controller - drives are not recognized

[Jimini]

Hey there,

I just bought a RAID controller to be able to address more drives. It is recognized as follows:
01:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 2108 [Liberator] (rev 05)

I do not want to use its RAID capabilities, since I am going to use mdadm to manage the array. Unfortunately, Gentoo does not recognize the drives connected to it. The controller is connectd to a backplane, which leads to the SATA disks. Since I never dealt with SAS before, I do not know if the kernel needs additional drivers or if I have to use some kind of management software.

Any help would be really appreciated.

Addendum: in the Web BIOS I can create a RAID0 for every disk - afterwards, every array / disk is recognized by Gentoo. But I am looking for a way to disable RAID functionality completely, since having to create a RAID0 for every disk at boot time would eliminate the hot swap functionality...

Addendum 2: alright, it seems as if the controller is not able to create a JBOD, which makes it pretty useless, when I want to use a software RAID.

Best regards,
Jimini
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"The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents." (H.P. Lovecraft: The Call of Cthulhu)

[krinn]

to get the drivers name, just use livecd and do lspci -k it should tell you the driver name to use.

for the drives problem, hardware raid card are not "simple controller", which generally mean, you cannot use a drive attach to it, you can only use arrays.
what's the difference? if the disk is not in an array, the disk will not be handle and will not work.

I don't really get your raid0 for every disk? You mean the card allow you to create a raid0 out of just 1 disk? Or probably more the card only allow you to create raid0 with all of them.
Some cards only offer raid0-1, some other offer more raid type, but may not show them if you lack enough drives (2 for raid 0&1, 3+ for other).

[Jaglover]

You need to use HBA passtrough mode to see the drives separately, I guess.
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[frostschutz]

Some raid controllers have alternative firmware available that makes them into non-raid controllers (seems kinda pointless, but...).

If the RAID controller has on disk metadata and you learn the magic bytes that mark it "single drive raid0" (usually at end of drive), you could use an external script to prepare drives accordingly. You'd need to understand the metadata format well to safely do so.

You could get a regular controller, HBA, or try your luck with port multipliers. 5 sata port hub for $15, only SATA II though, and not every controller handles multipliers well.

sata multipliers as common as usb hubs, unfortunately that never happened so there's sata port shortage everywhere.

[szatox]

[Mad Merlin]

The 2108 is a very common chipset that ships in IR (ie, RAID) mode by default, but you can usually reflash it to IT (ie, HBA) mode: https://www.servethehome.com/lsi-sas-2108-raid-controller-information-listing/
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[Jimini]

Thank you for your very useful answers. I never worked with RAID controllers before, so I learned a lot in the last weeks.

Now I bought a used and crossflashed Dell H200, which seems to work as expected: the drives are recognized seperately AND the OS can use their full capacity of 3TB (2,7 TiB).

Best regards,
Jimini
_________________
"The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents." (H.P. Lovecraft: The Call of Cthulhu)

[Mad Merlin]

[Jimini]