Asus PCI-DA2200 User Manual page 290

Mode 2 Expansion, on the other hand, requires the same
number of higher-capacity SCSI hard disk drives for a
given logical drive.
2 GB
Copy and Replace each of the member drives. Even
if one member drives fails during the Copy and
Replace, the logical drive will still be available for
access.
The figure above illustrates expansion of the same 4-
Gigabyte RAID 5 logical drive using Mode 2 Expansion.
Drives are copied and replaced, one by one, onto three
higher-capacity drives.
4.16 Dynamic Logical Drive Expansion
ASUS GUI RAID Manager: Array Management
RAID Expansion - Mode 2
2 GB 2 GB
The original logical drive
RAID 5 (4GB)
2 GB 2 GB
1
RAID 5 (4GB)
4 GB
2 GB
New
Drive
Copy and Replace
one of the member drives
(1/3)
In use
Unused
4-39