You can allocate disk pieces either while creating a new virtual disk, or by selecting an existing virtual disk (of a type that supports more than one piece) and choosing New from the Piece menu in the Virtual Disk Manager.
You can specify these parameters:
A list of available physical disk devices is displayed. You must choose a disk to place the piece on. When you select a disk, a map is displayed.
You can select a free section in the disk map; the offset and length fields will be updated appropriately. (You can also manually reduce the length field from the maximum size available, which is selected by default.)
If you are creating a simple virtual disk, you can overlay a single division with a single disk piece, in order to convert the division into a virtual disk. (Once a division is overlaid by a simple virtual disk, the division is deleted.)
For RAID 0, 1, 4 and 5 arrays, each piece must be of identical size. The first time you create a piece for such a disk, the piece length is fixed; all subsequent pieces you add to the array are forced to that size.
The Virtual Disk Manager software does not allow disk pieces to be added to an existing RAID 10 or RAID 53 configuration. If you need to add another piece, create the extra mirror or array piece with the Virtual Disk Manager, then exit and edit /etc/dktab manually to add the extra piece. The format of this file is described in dktab(F). You will need to move the definition of the new virtual disk piece so that it occurs before the definition of the virtual disk that uses it.
If the virtual disk has a cluster size defined, then the disk length (size) must be a multiple of the cluster size. If this is not the case then the length is decreased appropriately and you are prompted to confirm this new size.
All pieces must be allocated before the virtual disk can be created.