Installation guide

Glossary
Manual No. 775020 G-9
high degree of fault-tolerance. The rebuild operation will be carried out by
the controller automatically when a SCSI disk drive fails and both of the
following conditions are true:
• A “standby” SCSI disk drive of identical size is found attached to the
same controller.
• All of the system drives that are dependent on the failed disk are
redundant system drives, e.g., RAID 1, RAID 3, RAID 5, RAID 0+1.
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Note
The standby rebuild will only happen on the SAME
DAC960 controller, never across DAC960 controllers.
A Standby or Spare disk can be created by using RAID EzAssist or Global
Array Manager Client software.
During the automatic rebuild process, system activity continues as normal.
System performance may degrade slightly during the rebuild process.
To use the standby rebuild feature, you should always maintain a standby
(spare) disk in your system. When a disk fails, the standby disk will
automatically replace the failed drive and the data will be rebuilt. The system
administrator can disconnect and remove the bad disk and replace it with a
new disk. The administrator can then make this new disk a standby.
Stripe Order
The order in which SCSI disk drives appear within a drive group. This order
must be maintained, and is critical to the controller’s ability to ‘Rebuild’
failed drives.
Stripe Size
The stripe size is defined as the size, in kilobytes (1024 bytes) of a single I/O
operation. A stripe of data (data residing in actual physical disk sectors,
which are logically ordered first to last) is divided over all disks in the drive
group.
Stripe Width
The number of striped SCSI drives within a drive group.