Promise Technology FASTTRAK SX4300 - Manual (Page 51)

Chapter 5: Concepts
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• Choose a stripe block size equal to or smaller than the smallest cache buffer
found on any disk drive in your logical drive. A larger value slows the logical
drive down because disk drives with smaller cache buffers need more time
for multiple accesses to fill their buffers.
• If your data retrieval consists of fixed-size data blocks, such as some
database and video applications, choose that data block size as your stripe
block size.
Generally speaking, email, POS and webservers prefer smaller stripe block
sizes. Video and database applications prefer larger stripe block sizes.
Gigabyte Boundary
This feature is for fault tolerant logical drives (RAID 1, 5, 10 and 50). When a disk
drive has failed and the user cannot replace the drive with the same capacity or
larger, this feature permits you to install a replacement drive that is slightly
smaller (within 1 gigabyte) than the remaining working drives. This can be helpful
in the event that a drive fails and an exact replacement model is no longer
available.
You must set the Gigabyte Boundary feature to ON when you create your logical
drive. Gigabyte Boundary rounds the capacity of all disk drives to the common
whole GB drive size. For example, with the Gigabyte Boundary feature enabled,
the remaining working drives can be 80.5 GB and the replacement drive can be
80.3, since all are rounded down to 80GB. Note that the rounding function will
cause you to lose a small amount of capacity from each disk drive.
Initialization (Fast Init)
This function erases the Master Boot Record (MBR) in all of the selected disk
drives. Use this function when one or more disk drives has been used in a
previous logical drive.
Hot Spare Drive
Any extra drive that is not assigned to an array is designated Free in the View
Drive Assignments screen (see below). In order for a free drive to serve as a hot
spare drive, you must designate the free drive as a spare using the WebPAM
software.