LSI SATA 150 - Manual (Page 18)

1-4 Introduction
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1.1.5 Drive Roaming and Drive Migration
Note: Drive roaming and drive migration cannot be supported at
the same time. One or the other feature can be supported
at any one time, but not both features at the same time.
Drive roaming (also known as configuration on disk) occurs when the
hard drives are moved to different channels on the same controller and
the controller detects the RAID configuration from the configuration
information on the drives.
Configuration data is saved in both non-volatile random access memory
(NVRAM) on the RAID controller and on the hard drives attached to the
controller. This maintains the integrity of the data on each drive, even if
the drives have changed their target ID. Drive roaming is supported
across channels on the same controller, except when cluster mode is
enabled.
Drive roaming does not work if you move the drives to a new controller
and connect them to different channels. If you move drives to a new
controller, they must be on the same channel/target as they were on the
previous controller, in order to keep the same configuration.
You must power off the host system and the drive enclosure before you
use drive roaming.
Drive migration is the transfer of a set of hard drives in an existing
configuration from one controller to another. The drives must remain on
the same channel and must be reinstalled in the same order as in the
original configuration.
1.1.6 Logical Drive Deletion
The SATA 150 controllers allow you to delete unwanted logical drives and
then use the disk space for a new logical drive. You can use the
configuration utilities to create the next logical drive from the non-
contiguous free space (‘holes’) and from the newly created arrays.
You can still create sequential logical drives, without using the non-
contiguous segments. The utilities provide information about sequential
segments, non-contiguous segments, and physical drives that have not
been configured. You can use this information when you create logical
drives.