RAID5 and eSATA

Question

We have RAID5 (contains three disks):

Now we want to add eSATA disk to the same computer, but it musn't be part of RAID5, just single drive (it already has data on it). So, RAID5 with three disks stays untouched + eSATA disk as single (non-raid) drive also with all the data on it. Is this possible?

When we add it, it tries to add it to RAID5:

Answer 1

Maybe you should check the bios configuration. In serial - ata controller (raid enabled/disabled).

Answer 2

Probably this disk was previously used in a RAID5 array on an Intel onboard RAID controller, and then was reused as a single disk on some other controller (or even an Intel onboard controller configured in non-RAID mode). In this case, unless the array was properly destroyed in the RAID configuration utility of the original RAID controller, the disk still has Intel RAID metadata, and when you connect it to an Intel onboard RAID controller (the same or newer model), the controller tries to assemble the RAID array according to that metadata and fails because there are no other disks from that array.

To make this disk usable on an Intel onboard RAID controller again, you need to wipe Intel RAID metadata from it. Just removing the array in RAID BIOS, however, will also wipe the existing data, which you don't want to do.

I don't know a Windows utility which can remove RAID metadata (except a raw disk editor, but using it would require expert knowledge about RAID metadata formats). However, the dmraid utility for Linux can do it:

sudo dmraid -r -E /dev/sdX

(find the device name assigned to this particular disk and specify it instead of /dev/sdX; omit sudo if already working as root). You should do this on another machine to avoid messing up your working array, and maybe even disconnect all other disks and boot from a Live CD or USB stick (I would use SystemRescueCd for this task, but an Ubuntu 12.04 disk should work too; old versions might not have a recent enough dmraid).

And you should have a backup of the data on that disk anyway…

Answer 3

Typically with Intel onboard RAID controllers, when you just add a disk and don't explicitly configure it to be part of a volume, it will be just a disk (unless it has RAID headers with the format the RAID BIOS is expecting). However, it's possible your controller doesn't support this.

Try downloading and installing all applicable BIOS and firmware updates for your board, and then try again.

Make sure you're not creating a new volume after you plug the disk in...