HP 6400/8400 User Manual page 134

controller event A significant occurrence involving any storage system hardware or software component reported
by the controller to HP P6000 Command View.
controller pair Two connected controller modules that control a disk array.
corrective action See CAC.
code
CRITICAL Condition A drive enclosure EMU condition that occurs when one or more drive enclosure elements have
failed or are operating outside of their specifications. The failure of the element makes continued
normal operation of at least some elements in the enclosure impossible. Some enclosure elements
may be able to continue normal operations. Only an UNRECOVERABLE condition has precedence.
This condition has precedence over NONCRITICAL errors and INFORMATION condition.
CRU Customer replaceable unit. A storage system element that a user can replace without using special
tools or techniques, or special training.
customer See CRU.
replaceable unit
D
data entry mode The state in which controller information can be displayed or controller configuration data can
be entered. On the Enterprise Storage System, the controller mode is active when the LCD on the
HSV Controller OCP is Flashing.
default disk group The disk group that is created when the array is initialized. The minimum number of disks the
group can contain is eight. The maximum is the number of installed disks.
Detailed Fault An HSV Controller OCP display that permits a user to view detailed information about a controller
View fault.
device channel A channel used to connect storage devices to a host I/O bus adapter or intelligent controller.
device ports The controller pair device ports connected to the storage system's physical disk drive array through
the Fibre Channel drive enclosure. Also called a device-side port.
device-side ports See device ports.
DIMM Dual inline memory module. A small circuit board holding memory chips.
dirty data The write-back cached data that has not been written to storage media even though the host
operation processing the data has completed.
disk drive A carrier-mounted storage device supporting random access to fixed size blocks of data.
disk drive blank A carrier that replaces a disk drive to control airflow within a drive enclosure whenever there is
less than a full complement of storage devices.
disk drive A unit that holds storage system devices such as disk drives, power supplies, fans, I/O modules,
enclosure and transceivers.
disk failure A method by which a controller pair reserves drive capacity to take over the functionality of a
protection failed or failing physical disk. For each disk group, the controllers reserve space in the physical
disk pool equivalent to the selected number of physical disk drives.
disk group A named group of disks selected from all the available disks in a disk array. One or more virtual
disks can be created from a disk group. Also refers to the physical disk locations associated with
a parity group.
disk migration A physical disk drive operating state. A physical disk drive can be in a stable or migration state:
state
disk replacement The time that elapses between a drive failure and when the controller starts searching for spare
delay disk space. Drive replacement seldom starts immediately in case the "failure" was a glitch or
temporary condition.
DR group failover An operation that reverses data replication direction so that the destination becomes the source
and the source becomes the destination. Failovers can be planned or unplanned and can occur
between DR groups or managed sets (which are sets of DR groups).
134 Glossary
Stable—The state in which the physical disk drive has no failure nor is a failure predicted.
Migration—The state in which the disk drive is failing, or failure is predicted to be imminent.
Data is then moved off the disk onto other disk drives in the same disk group.