Gigabyte Boundary - Western Digital WD Serial ATA RAID Controller User Manual

WD SERIAL ATA RAID CONTROLLER
USER MANUAL

Gigabyte Boundary

The Gigabyte Boundary feature is designed for mirrored arrays (RAID 1) in which a drive has
failed and the user cannot replace the drive with the same capacity or larger drive. Instead, the
Gigabyte Boundary feature permits the installation of a replacement drive that is slightly
smaller (within 1 GB) 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, the WD SATA RAID Controller 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 80 GB. This
permits the smaller drive to be used. Please note that users will lose a small amount of
available storage capacity from both drives 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 to maintain data integrity.
EASYBUILD OPTIONS AND FEATURES - 24