Avago Technologies 3ware SAS 9750-16i4e - Manual (Page 310)

Appendix A. Glossary
298 3ware SATA+SAS RAID Controller Card Software User Guide, Version 10.2
• 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.
• Phy. Phys are transceivers that transmit and receive the serial data stream
that flows between the controller and the drives. 3ware 9750 controllers
have multiple phys. These phys are associated with virtual ports (vports)
by 3ware software to establish up to 127 potential connections with the
SAS or SATA hard drives.
• Phy Identifier. The ID number (0-7) assigned to each of the 8 phys on the
9750 controller.
• Port. 3ware controller models have one or many ports (typically 4, 8, 12,
16, 24, or 28). 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. On 9750 series controllers, connections are made
with phys and vports (virtual ports). See “phy” and “VPort”.
• Port ID . A unique identifier for a specific port in a system. Also called a
drive ID.
• Queuing . SATA drives can use Native Command Queuing (NCQ) to
improve performance in applications that require a lot of random access
to 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. 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.
• 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).
• Rapid RAID Recovery. The Rapid Raid Recovery feature increases the
speed with which a redundant unit can be made redundant again when a
rebuild is required. It can also increase the speed of verification or
initialization that may occur in the event of an unclean shutdown.
• Read Cache. Read Cache stores data from media locally on the controller
to improve read access times for applications. The 3ware Read Cache
feature also includes an Intelligent Mode, which enables Intelligent Read
Prefetch (IRP). IRP includes a typical read-ahead caching method which
is used to proactively retrieve data from media and store it locally on the
controller with the anticipation that it may be requested by the host.
• Rebuild task schedule . The specification for when rebuilding, may
occur, including start time and duration.
• 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).