The output I get is the same for every instance I run (just after booting the live CD, after swapoff -a and after install of dmraid).
ubuntu@ubuntu:~$ sudo vol_id /dev/sda ID_FS_USAGE=raid ID_FS_TYPE=via_raid_member ID_FS_VERSION=1 ID_FS_UUID= ID_FS_UUID_ENC= ID_FS_LABEL= ID_FS_LABEL_ENC= ID_FS_LABEL_SAFE= ubuntu@ubuntu:~$
So it seems that vol_id knows that I have raid.
The output I get is the same for every instance I run (just after booting the live CD, after swapoff -a and after install of dmraid).
ubuntu@ubuntu:~$ sudo vol_id /dev/sda via_raid_ member
ID_FS_USAGE=raid
ID_FS_TYPE=
ID_FS_VERSION=1
ID_FS_UUID=
ID_FS_UUID_ENC=
ID_FS_LABEL=
ID_FS_LABEL_ENC=
ID_FS_LABEL_SAFE=
ubuntu@ubuntu:~$
So it seems that vol_id knows that I have raid.