I have an Adaptec RAID-Controller and created an RAID-1(Mirroring) succesfully.

Now I have installed Ubuntu Server 12.04.3. When I type fdisk -l I get this output:

bf@fileserver:~$ sudo fdisk -l

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000

Disk /dev/sda doesn't contain a valid partition table

Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000

Disk /dev/sdb doesn't contain a valid partition table

Disk /dev/sdc: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders, total 156301488 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
Disk identifier: 0x0004c454

    Device Boot      Start         End      Blocks   Id  System
/dev/sdc1   *        2048      499711      248832   83  Linux
/dev/sdc2          501758   156301311    77899777    5  Extended
/dev/sdc5          501760   156301311    77899776   8e  Linux LVM

Disk /dev/mapper/fileserver--vg-root: 75.6 GB, 75606523904 bytes
255 heads, 63 sectors/track, 9191 cylinders, total 147668992 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
Disk identifier: 0x00000000

Disk /dev/mapper/fileserver--vg-root doesn't contain a valid partition table

Disk /dev/mapper/ddf1_Data: 1000.1 GB, 1000065728512 bytes
255 heads, 63 sectors/track, 121584 cylinders, total 1953253376 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000

Disk /dev/mapper/ddf1_Data doesn't contain a valid partition table

Disk /dev/mapper/fileserver--vg-swap_1: 4160 MB, 4160749568 bytes
255 heads, 63 sectors/track, 505 cylinders, total 8126464 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
Disk identifier: 0x00000000

Disk /dev/mapper/fileserver--vg-swap_1 doesn't contain a valid partition table

The 80 GB HDD is for the System The 1000.2 GB HDD should be for my data. But I'm a bit confused becauser there are listed two 1000.2 GB HDDs, due the Hardware RAID shoudln't there be only one HDD vissible to the OS? (I have two 1000.2 GB HDDs in an Raid-1 Array)

dmraid gives me

bf@fileserver:~$ sudo dmraid -r
/dev/sdb: ddf1, ".ddf1_disks", GROUP, ok, 1953253376 sectors, data@ 0
/dev/sda: ddf1, ".ddf1_disks", GROUP, ok, 1953253376 sectors, data@ 0

so It seems to be ok? But how do I partitionate this disks and which one should I mount(sdb or sda?)

Hope you can help me thx Florian