RAID1 shows up twice in fdisk

Question

I have a RAID1 that I'm trying to mount in Ubuntu. When I enter

sudo fdisk -l

I see the RAID show up twice at /dev/sdc and /dev/sdd. I don't see anything different about the info under them so I'm wondering why I'm seeing it twice? It looks like:

ss113@haf-linux:/localRaid1$ sudo fdisk -l /dev/sdc
Disk /dev/sdc: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x7e7b1232

Device     Boot  Start        End    Sectors  Size Id Type
/dev/sdc1  *      2048     718847     716800  350M  7 HPFS/NTFS/exFAT
/dev/sdc2       718848 3906990079 3906271232  1.8T  7 HPFS/NTFS/exFAT


ss113@haf-linux:/localRaid1$ sudo fdisk -l /dev/sdd
Disk /dev/sdd: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x7e7b1232

Device     Boot  Start        End    Sectors  Size Id Type
/dev/sdd1  *      2048     718847     716800  350M  7 HPFS/NTFS/exFAT
/dev/sdd2       718848 3906990079 3906271232  1.8T  7 HPFS/NTFS/exFAT

I'm tried to mount the /dev/sdc one and it says:

ss113@haf-linux:/localRaid1$ sudo mount /dev/sdc /localRaid1/
mount: /localRaid1: unknown filesystem type 'isw_raid_member'.

I read that I have to use mdadm first on it?

For the record if you're wondering why it is formatted as HTFS/exFAT is because I have dual-booting with Windows and I later added Ubuntu to the mix.

If you are interested here is the full fdisk -l that lists everything on the system: https://pastebin.com/ScwhK6Qm

Answer 1

Raid1 isn't show up twice, /dev/sdc and /dev/sdd are the Raid member drive, so it should have there own entry in /dev.

It looks like Ubuntu isn't assemble those two drives to RAID1 with the metadata on the drives. If the system successfully assemble the RAID, you should see something like '/dev/md125' in fdisk -l. You can also use 'cat /proc/mdstat' to check if there are any Raid Volume in the system.

And you should not mount any Raid member drive directly, you should mount the Raid Volume to the mount point like 'mount /dev/md125 /localRaid1'.

You can try reboot your system to let mdadm daemon automatically assemble the Raid base on /dev/sdc and /dev/sdd metadata. If failed, you may manually assemble them using command like 'mdadm -A /dev/md125 /dev/sdc /dev/sdd'.

BTW, How did you create RAID, using Hardware Raid Card or using mdadm to create Software Raid?