Manual RAID definition

Block map

The block map displays the currently configured layout of the array. Data blocks are numbered starting with 1, and parity blocks are marked P.

Disk order and missing disks

The disk order section (bottom of the window) shows the current ordering of disks in the array. The topmost disk in the list corresponds to the leftmost disk in the block map. Use the Move up and Move down toolbar buttons to change the disk order.

If you are recovering a RAID5 with a missing disk, use the corresponding toolbar buttons to add one. The missing disk is reconstructed from RAID5 parity data.

Parity parameters

This section controls the use of parity blocks, the column on which the parity starts, and how the parity block position moves from row to row. The block map changes immediately as you adjust the parameters.

Block parameters

Size

Specify RAID block size here.

Start

If RAID members are offset from the start of their parent disk or partition, use this field to specify the distance from the start of the parent to the start of the RAID member. The distance is measured in 512-byte sectors.

Data ordering

Only applicable to parity arrays, this setting controls how the data is arranged in relation to the parity blocks. There are two options, Symmetric (also called Synchronous, or Data Continuation) and Asymmetric (also called Asynchronous, or Data Restart).

Symmetric
1 2 3 P
5 6 P 4
9 P 7 8
P 10 11 12
Asymmetric
1 2 3 P
4 5 P 6
7 P 8 9
P 10 11 12

The difference between Symmetric and Asymmetric data layouts in a RAID5, with relevant data blocks highlighted.

Finalizing a RAID

Once satisfied with the layout, click Use virtual RAID to create a virtual RAID device, which you can then process with the filesystem scanner.