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NCQ must be supported by the drive. NCQ must be turned on in both the
drive and the RAID controller. By default, the RAID unit’s queue policy
is disabled when creating a unit.
•
Non-redundant units.
A disk array (unit) without fault tolerance (RAID
0, single disk, or JBOD.).
•
OCE (Online Capacity Expansion).
The process of increasing the size of
an existing RAID unit without having to create a new unit. See also
migration
.
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Parity.
Information that the controller calculates using an exclusive OR
(XOR) algorithm and writes to the disk drives in RAID 5, RAID 6, and
RAID 50 units. This data can be used with the remaining user data to
recover the lost data if a disk drive fails.
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PCB
. Printed circuit board.
•
P-Chip.
PCI interface chip that connects the PCI bus to the high-speed
internal bus and routes all data between the two using a packet switched
fabric. There is one P-chip per controller card.
•
Port.
A controller has one or many ports (typically 4, 8, 12, 16, or 24).
Each port can be attached to a single disk drive. On a controller with a
Multi-lane™ serial port connector, one connector supports four ports.
•
Port ID
. A unique identifier for a specific port in a system. Also called a
drive ID.
•
RAID.
Redundant array of inexpensive disks, combined into a unit
(array), to increase your storage system’s performance and provide fault
tolerance (protection against data loss).
•
Rebuild task schedule
. The specification for when rebuilding, may
occur, including start time and duration.
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Rebuild a unit
. To generate data on a new drive after it is put into service
to replace a failed drive in a fault tolerant unit (for example, RAID 1, 10,
5, 6, or 50).
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Redundancy.
Duplication of data on another drive or drives, so that it is
protected in the event of a drive failure.
•
Remove a drive.
The process of making a drive unavailable to the
controller.
•
Remove a unit.
The process of making a unit unavailable to the
controller and the operating system. After a unit is removed it can be hot
swapped out of the system. This is sometimes referred to as exporting a
unit.
•
RLM (RAID Level Migration).
The process of using an existing unit of
one or more drives and converting it to a new RAID type without having
