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Configuration
XX102-00-00 Rev 203 KOL-RAID3 RAID Storage Systemd
Gigabyte Boundary
The Gigabyte Boundary feature is designed for fault tolerant arrays (RAID 1, 0+1, 3, 5, 30, and 50) 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, a 20.5GB drive would be rounded down to 20GB). 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 unit 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 array
is created. When enabled, the Gigabyte Boundary feature rounds the drive capacity of all drives to the common whole
GB drive size. For example, with the Gigabyte Boundary feature enabled, the remaining working drives can be 20.5GB
and the replacement drive can be 20.3, since all are rounded down to 20GB. This permits the smaller drive to be used.
Please note that users will lose a small amount of available storage capacity from each drives in order to arrive at a
common drive size.
Choosing Stripe Block Size
There are two issues to consider when selecting the Stripe Block Size.
First, you should choose a Stripe Block Size equal-to or smaller than the smallest cache buffer found on any array disk
drive. Selecting a larger value slows the array down because disk drives with smaller cache buffers need more time
for multiple accesses to fill their buffers.
Secondly, if your data retrieval consists of fixed data blocks, such as with some database or video applications – then
you should choose that size as your Stripe Block Size.