isw_raid_member (Intel Rapid Storage) on Debian

In my case, I'm not sure how it worked on Debian 8, but on Debian 10, Intel RST is handled by dmraid, and automatically assembled a virtual block device at /dev/mapper/isw_<10lettershere>_Volume_0000

dmesg showed these relevant lines:

[21120.363597] md/raid:mdX: device sda operational as raid disk 0
[21120.363600] md/raid:mdX: device sdb operational as raid disk 1
[21120.363601] md/raid:mdX: device sdc operational as raid disk 2
[21120.363602] md/raid:mdX: device sdd operational as raid disk 3
[21120.364249] md/raid:mdX: raid level 5 active with 4 out of 4 devices, algorithm 0

dmsetup listed the device:

rsaxvc@localghost:/$ sudo dmsetup ls
isw_bcegjbdfjj_Volume_0000  (254:0)

Probing the block device for partitions with partprobe found them:

rsaxvc@localghost:/$ sudo partprobe /dev/mapper/isw_<10letters>_Volume_0000
rsaxvc@localghost:/$ ls /dev/mapper/isw_*
  /dev/mapper/isw_<10letters>_Volume_0000  
  /dev/mapper/isw_<10letters>_Volume_0000p1  
  /dev/mapper/isw_<10letters>_Volume_0000p2

At this point I was able to mount one of the partitions that another OS had created on the Intel RST volume under Debian 10. These are the relevant versions that came with Debian 10 on my machine:

rsaxvc@localghost:~$ dmraid --version
dmraid version:     1.0.0.rc16 (2009.09.16) shared 
dmraid library version: 1.0.0.rc16 (2009.09.16)
device-mapper version:  4.39.0
rsaxvc@localghost:~$ uname -a
Linux localghost 4.19.0-13-amd64 #1 SMP Debian 4.19.160-2 (2020-11-28) x86_64 GNU/Linux
rsaxvc@localghost:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 10 (buster)
Release:    10
Codename:   buster