HP NetRAID Installation and Configuration Guide

Glossary
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SAF-TE: SCSI Access Fault-Tolerant Enclosure; a processor that manages a
hot-swap mass storage cage or enclosure.
SCSI Channel: The HP NetRAID Series adapters control the disk drives
via SCSI-2 buses called "channels" over which the system transfers data in
Fast-and-Wide, Ultra SCSI, or Ultra-2 SCSI mode. Each HP NetRAID-3Si and
HP NetRAID adapter can control up to three SCSI channels. Each HP
NetRAID-1Si and HP NetRAID-1 adapter can control one SCSI channel.
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 a SCSI bus must have a different SCSI address
number (Target) from 0 to 15, but not 7, which is reserved for the SCSI
controller. A SCSI ID is also be reserved for the SAF-TE processor, if one is
present on the mass storage enclosure.
Stripe Size: The amount of data contiguously written to each disk. Also called
"stripe depth." You can specify stripe sizes of 2-KB, 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