DIY Approaches to RAID 10 Recovery

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DIY Approaches to RAID 10 Recovery

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If the controller has failed

You can try to connect the disks to the identical controller. If you have a Linux-based software RAID 10 array in a NAS device, try using Linux as described on the manual NAS recovery page.

However, it is recommended to create disk image files first to prevent the data loss situation if you accidentally mix up the disks. If the controller initializes the array based on this wrong disk order, you lose exactly half of the array data.

If you cannot use an identical controller or you accidentally deleted your array and it is not accessible despite the controller is fine, you need to disconnect disks from the failed controller and connect the disks to a PC separately. Then you should pick out RAID 0 from RAID 10.

How to get RAID 0 from the member disks of RAID 10

A typical RAID10 array consists of two identical disk sets (due to mirroring) of RAID0 arrays. Therefore you should have one full set of disks belonging to RAID 0 before you start the recovery. To get such a set you need to exclude one disk from each pair.

• The resultant set must contain exactly N/2 disks. If there are less than N/2 disks in the set, the array is unrecoverable.
• If the controller has failed but disks are OK, you can use any one disk from each pair in the set.
• If one of the disks in the pair is mechanically damaged then you should exclude this failed disk.

Once you got the full set of disks, all you need is to recover RAID 0 using disks from this set.

To determine the disks forming RAID 0, you can use any disk editor tool to analyze and compare the disks contents. For example you can try WinHex or ZAR. The demo version of either will do. When using such a tool, pay attention to the disk names and to how these names correlate to the real devices. For this you need to take into account the following:

In the Disk Management (right click on the Computer - Manage - Disk Management) disks are displayed as Disk 0, Disk 1 and so on. In various tools you can meet different names, like \\.\PhysicalDrive 0 (in R-Studio) or HD0: (in WinHex) or Disk 0 - Model (in ZAR data recovery software).

Disk Management	R-Studio	WinHex	ZAR
Disk 0	\\.\PhysicalDrive0	HD0:	Disk 0 - [Model Name]
Disk 1	\\.\PhysicalDrive1	HD1:	Disk 1 - [Model Name]
Disk 2	\\.\PhysicalDrive2	HD2:	Disk 2 - [Model Name]

To get the actual port number, see the detailed information on the device in the Disk Management (right click on the disk - select Properties).

For SATA disks you need to know a number of physical port on the motherboard (see Location Channel) and then compare with a port number printed on the motherboard (typically, all the ports are labeled).

In the photo above, two SATA port labels, Port 0 and Port 5 are clearly visible; also, one can make out parts of labels for ports 1 and 4. The cable is plugged into port 3.

As a last resort there is always the option of connecting the disks one by one.

Once you connect the disks to a computer separately and have got the disks set as for RAID 0, you should set about the RAID recovery. Read more on how to recover RAID 0.