Toshiba Qosmio G20 (PQG21) - Manual (Page 213)

User’s Manual E-3
TOSHIBA RAID
■ Boot menu
When 2 hard disk drives are connected, it is possible to select which
hard disk drive to boot from in the boot menu. However, if a RAID
configuration is used, the 2 hard disk drives are recognized as 1 drive
and there is no change in the boot configuration no matter which hard
disk drive is selected.
■ When using a RAID-1 (mirroring) or RAID-0 (Striping) configuration, the
additional hard disk drive’s capacity must be equal to or more than the
capacity of the existing hard disk drive.
■ The hard disk drives used in the RAID configuration should not be
removed and used in other computers.
■ When using the RAID-1 (mirroring) configuration, the operating system
recognizes the lesser capacity of the 2 hard disk drives. For example,
if a 60 GB and an 80 GB hard disk drive are used in the mirroring
configuration, the OS will recognize the capacity as a 60 GB hard disk
drive. The additional 20 GB capacity (over the 60 GB hard disk drive) of
the 80 GB hard disk drive cannot be used.
■ If a hard disk drive had been replaced, execute the rebuild command
and rebuild the RAID-1 (mirroring) configuration.
■ Implementing the media checking schedule
Media checks should be carried out regularly to ensure even more
stable operation of the RAID configuration and to make it easier for
maintenance and repair measures to be carried out in case of hard disk
drive failures. For RAID-1 with data redundancy, if one of the hard disk
drives fails, the hard disk drive can be replaced and its data
reconstructed from the other hard disk drive which did not fail.
However, if the hard disk drive that did not fail has bad blocks, etc.,
it is possible that portions of data might not be recovered and a system
failure might occur.
Therefore, to ensure that such situations do not happen, perform
RAID-1 media checks regularly. The TOSHIBA RAID Console is set by
default to perform media checks once a month.
■ When using RAID-0 (Striping) configuration, the size seen by the OS is
twice that of the smaller of the two HDD units in the RAID configuration.
■ When using RAID-0 (Striping) configuration, all data on both disks will
be lost, even if only one of the two disk drives fails.