3Ware 9550SX-4LP User Manual page 256

Chapter A. Glossary
is running. However, RAID 5 initialization done through the 3ware BIOS
does erase any existing data.
• JBOD.
bunch of disks." Note that earlier versions of the 3ware RAID controller
exported JBODs to the OS. By default, this is not the case in 9000-series
controllers. However, a policy in 3BM can be set that allows JBODs to be
seen by the OS. By default, individual drives must be configured as
Single Disks in order to be made available to the OS.
•
Migration.
change can be to expand the capacity of the array (OCE), change the
stripe size of the array, change the array from redundant to non-redundant,
or to change the array from non-redundant to redundant
• Mirrored disk array.
so that each provides a backup for the other. If one drive fails, the data is
preserved on the paired drive. Mirrored disk arrays include RAID 1 and
RAID 10.
• NCQ (Native Command Queuing).
performance of SATA hard disks in some applications that require a lot of
random access of data, such as server-type applications. When NCQ is
enabled, the commands are reordered on the drive itself.
NCQ must be supported by the drive and is only available on the 9550SX
and 9590SE controllers. 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.
single disk, or JBOD.).
• OCE (Online Capacity Expansion).
an existing RAID unit without having to create a new array. See also
migration.
• Parity.
(XOR) algorithm and writes to the disk drives in RAID 5 and RAID 50
units. This data can be used with the remaining user data to recover the
lost data if a disk drive fails.
•
PCB
•
P-Chip.
internal bus and routes all data between the two using a packet switched
fabric. There is one P-chip per controller card.
•
Port ID
drive ID.
•
Rebuild task schedule
occur, including start time and duration.
246
An unconfigured single drive. The acronym is derived from "just a
The process of changing the characteristics of a unit. The
A pair of drives on which the same data is written,
A disk array without fault tolerance (RAID 0,
Information that the controller calculates using an exclusive OR
. Printed circuit board.
PCI interface chip that connects the PCI bus to the high-speed
. A unique identifier for a specific port in a system. Also called a
. The specification for when rebuilding, may
3ware Serial ATA RAID Controller User Guide
.
A feature designed to improve
The process of increasing the size of