HP SureStore E Disk Array 12H User's and Service Manual (C5445-90901, September 1999)

Glossary
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Glossary
Data Redundancy Capacity Data Redundancy Capacity is the capacity required to support the RAID
0/1 and RAID 5 storage techniques used by the disk array for Data
Redundancy. This capacity is managed by the Disk Array Controller
and cannot be altered or reduced.
Data Transfer Rate The Data Transfer Rate is the speed at which data is transferred
between a host computer system and a peripheral.
Disk Array Controller The Disk Array Controller implements the HP AutoRAID
™
Array
Technology and Balancing of the data. The Disk Array Controller
manages all data transfers to and from the host computer and also to
and from each Disk Module.
Disk Module The disk array enclosure holds up to twelve Disk Modules. Each Disk
Module contains a single hard disk assembly.
Disks Not in Use A Disk Not in Use is any disk that is installed in the array enclosure but
is not included in the array configuration.
Disk Stamp A unique identifying code written to each disk. The Disk Stamp
identifies the disk as belonging to the set of disks installed in the array.
The stamp is written to the disk when it is included in the array.
Downing A Disk The process of logically removing a disk from the array configuration.
Typically done before testing a disk, downing a disk has much the same
effect as physically removing it from the array enclosure.
DRR DRR, or Disable Remote Reset. When DRR is ON or enabled (default),
it prevents a host SCSI reset from resetting both disk array SCSI buses.
With DRR set to ON, disk array controllers are not allowed to reset
their own SCSI bus, even if the host resets that controller. If DRR is set
to OFF, a host SCSI reset will also allow that controller to reset both
disk array SCSI buses.
Dynamic Data Migration Dynamic Data Migration is the process of moving data that is accessed
frequently (according to both the Disk Stamp and the Time Stamp,
which is updated when the data is written) into RAID 0/1 space, which
is optimized for performance, and also moving data that is accessed
less often into RAID 5 space, which is optimized for its higher storage
density.