Promise Technology 150TX2 - Manual (Page 31)

Chapter 2: Getting Started
27
Gigabyte Boundary
The Gigabyte Boundary feature is designed for mirrored arrays (RAID 1 or RAID
0+1) in which a drive has failed and the user cannot replace the drive with the
same capacity or larger. Instead, the Gigabyte Boundary feature permits the
installation of a replacement drive that is slightly smaller (within 1 gigabyte) than
the remaining working drive (for example, an 80.5 GB drive would be rounded
down to 80 GB).
This can be helpful in the event that a drive fails and an exact replacement
model is no longer available. Without this feature enabled, FastTrak S150
TX2plus will NOT permit the use of a replacement drive that is slightly smaller
than the remaining working drive.
For the Gigabyte Boundary feature to work, the Gigabyte Boundary feature must
be set to ON when the original mirrored array is created. When enabled, the
Gigabyte Boundary feature rounds the drive capacity of both drives to the
common whole GB drive size. For example, with the Gigabyte Boundary feature
enabled, the remaining working drive can be 80.5 GB and the replacement drive
can be 80.3, since both are rounded down to 80GB.
This permits the smaller drive to be used. Please note that users will lose a
small amount of available storage capacity from both drives in order to arrive at
a common drive size.
Note
Gigabyte Boundary is automatically disabled when creating
a mirrored array (RAID 1) from an existing drive (versus
using two brand new drives). This protects the existing
drive’s partition table in order to maintain data integrity.