HP Surestore Disk Array 12h - And FC60, Руководство для продвинутых пользователей, Страница: 447 / 466

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frame
The smallest indivisible unit of application-data transfer used by Fibre Channel. Frame
size depends on the hardware implementation and is independent of the application
software. Frames begin with a 4-byte Start of Frame (SOF), end with a 4-byte End of
Frame (EOF), include a 24-byte frame header and 4-byte Cyclic Redundancy Check
(CRC), and can carry a variable data payload from 0 to 2112 bytes, the first 64 of which
can be used for optional headers.
FRU (Field Replaceable Unit)
A disk array hardware component that can be removed and replaced by a customer or
Hewlett-Packard service representative.
global hot spare
A disk that is powered up and electrically connected to a disk array but not used until a
disk failure occurs. A global hot spare is a dedicated, on-line, backup disk that cannot
be used to store user data during normal disk array operation. If any disk in a LUN fails,
the disk array automatically begins rebuilding the failed disk’s content on an available
global hot spare. When the rebuild process completes, the LUN functions normally,
using the global hot spare as a replacement for the failed disk. Up to six disks (one for
each channel) can be assigned as global hot spares.
hardware path
See primary disk array path.
HBA
See adapter.
high availability
The technique of designing systems that remain operational even if a hardware or other
type of failure occurs. The disk array achieves high availability by using redundant data
and global hot spare disks to maintain access to user data in the event of a disk failure.
Redundant hardware assemblies also ensure high availability in the event of a failure.