HP D5970A - NetServer - LCII Configuration Manual page 130

Glossary
Channel: An electrical path for the transfer of data and control information
between a disk and a disk controller.
Format: The process of writing zeros to all data fields in a physical drive (hard
drive) and to map out unreadable or bad sectors. Because most hard drives are
factory formatted, formatting is usually only done if a hard disk generates several
media errors.
GB: A gigabyte; an abbreviation for 1,073,741,824 (2 to the 30th power) bytes
used for memory or disk capacities.
Hot Spare: An idle, powered-on, stand-by disk module ready for use should
another disk module fail. It does not contain any user data. Up to eight disk
modules can be assigned as hot spares. A hot spare can be dedicated to a single
redundant array, or it can be part of the global hot-spare pool for all the arrays.
Only one hot spare can be dedicated to a given array.
When a disk fails, the controller's firmware automatically replaces and rebuilds
the data from the failed disk onto the hot-spare disk. Data can only be rebuilt
from logical drives with redundancy (RAID levels 1, 3, 5, 10, 30, or 50; not
RAID 0), and the hot-spare disk must have sufficient capacity. The system
administrator can replace the failed disk module and designate the replacement
disk module as a new hot spare.
Hot Swap Disk Module: Hot swap modules allow a system administrator to
replace a failed disk drive in a server without powering down the server and
suspending network services. The hot swap module simply pulls out from its slot
in the drive cage because all power and cable connections are integrated into the
server backplane. Then the replacement hot-swap module can slide into the slot.
Hot swapping only works for RAID 1, 3, 5, 10, 30, and 50 configurations.
I O: Intelligent Input/Output (I
2
architecture independent of the network operating system and the peripheral
devices supported. I
modules (OSMs) and hardware device modules (HDMs). I
system performance by shifting I/O computations from the system CPUs to
dedicated I/O processors. It also makes driver management easier and less
expensive.
Initialization: The process of writing zeros to the data fields of a logical drive
and generating corresponding parity to put the logical drive in a Ready state.
Initializing erases previous data, generating parity so that the logical drive will
pass a Consistency Check. Arrays work without initializing, but they may fail a
Consistency Check because parity fields may not have been generated.
124
O) is an industry-standard, I/O subsystem
2
O uses drivers that are split into operating system services
2
O increases overall
2