HP D5970A - NetServer - LCII Installation And Configuration Manual page 142

Glossary
SCSI Disk Status: A SCSI disk module (physical drive) can be in one of five
states:
Ready: a powered-on and operational disk that has not been configured.
Online: a powered-on and operational disk that has been configured.
Hot Spare: a powered-on, stand-by disk ready for use should a disk fail.
Not Responding: the disk is not present, not powered-on, or has failed.
Failed: errors on the disk have caused it to fail, or you have used an HP
NetRAID utility to take the drive offline.
Rebuilding: a disk in the process of having data restored from one or
more critical logical drives.
SCSI ID: Each SCSI device on an HP NetRAID Series SCSI bus must have a
different SCSI address number (Target) from 0 to 15, but not 7, which is reserved
for the SCSI controller. Set the SCSI ID switch on each disk drive module to its
correct SCSI address. Consult your HP NetServer documentation and chassis
labels for the correct switch settings.
Stripe Size: The amount of data contiguously written to each disk. Also called
"stripe depth." You can specify stripe sizes of 4 KB, 8 KB, 16 KB, 32 KB, 64
KB, and 128 KB, for each logical drive. For best performance, choose a stripe
size equal to or smaller than the block size used by your host operating system. A
larger stripe depth produces higher read performance, especially if most of the
reads are sequential. For mostly random reads, select a smaller stripe width. You
may specify a stripe size for each logical drive. A 128-KB stripe requires 8 MB of
memory.
Stripe Width: The number of disk modules across which the data is striped.
Equivalent to the number of disks in the array.
Striping: Segmentation of logically sequential data, such as a single file, so that
segments can be written to multiple physical devices in a round-robin fashion.
This technique is useful if the processor is capable of reading or writing faster
than a single disk can supply or accept it. While data is being transferred from
the first disk, the second disk can locate the next segment. Data striping is used
in some modern databases and in certain RAID devices.
Virtual Sizing: This setting, when enabled for a logical drive, causes the
controller to report the logical drive size as 82 GB even though the actual
physical capacity is much less. The "virtual" space allows for online capacity
expansion.
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