|This object describes how to assign the storage space.
The value 'differentAdapter' means select drives from different adapter/channel,
system will look for space on another array only if it is on a separate adapter/channel.
The value 'differentDrive' means select different drive, system will look for space on another array.
The value 'anyDrive' means select any available drive, system will look for space on any array,
including the original.
The value 'none' means the way to assign the storage space is not specified,
in this case the system will allocate the storage with the default criteria in the following order:
1. the storage from different adapter
2. the storage from different drive
3. the storage from any drive