User manual

SuperTrak SX6000™ User Manual Chapter 3
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Gigabyte Boundary
The Gigabyte Boundary feature is designed for fault tolerant arrays (RAID 1, 0+1, 3,
and 5) 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 20.5 GB drive would be rounded down to 20 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, SuperTrak SX6000 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 20.5 GB 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 drive in order to arrive at a
common drive size.
NOTE: The Gigabyte Boundary feature 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.
Creating a RAID 0 Array
In the “Define Array Definition Menu” section (see Figure 8), use the [Spacebar] to cycle
through array types and select "RAID 0" for RAID Level. You will be joining the drives
you assign to this array together and splitting (or striping) data writes among the
members of the array. Each member of such an array will no longer be readable as an
independent drive if removed from the array. The capacity of the array will equal the
capacity of the smallest drive multiplied by the number of drives within the array.
Changing Stripe Block Size
For RAID 0 arrays, SuperTrak SX6000 will allow you to change the stripe
block size. The default is 64K. However, certain application environments
may perform optimally with different. To change the block size, use the
[Arrow] keys to highlight the field and the [Spacebar] to cycle through the
available size selections (4, 8, 16, 32 or 64K).
NOTE: you cannot change the block size after the array has been created.
Assigning Drives to a RAID 0 Array
Under the “Drive Assignments” section, highlight a drive and, with the
[Spacebar], change the “Assignment” option to “Y” to add the drive to the disk
array. Press [Ctrl-Y] to save the disk array information. The initial “Define
Array Menu” screen will appear after you have pressed [Ctrl-Y]. You will see
the array defined. You may select another Array number to define or you may
[ESC] to exit and return to the “Main Menu” of SuperBuild.
Setting the Initialize Function
For RAID 0 arrays, SuperTrak SX6000 sets “Initialize” to “OFF”.