HP Smart Array 6400 Series Controllers Support Guide, September 2007

Glossary
array A set of physical disks configured into one or more logical drives. Arrayed disks have significant
performance and data protection advantages over non-arrayed disks.
array accelerator A component of some Smart Array Series controllers that dramatically improves disk read and
write performance by providing a buffer. Data integrity is protected by a backup battery and
ECC memory.
array capacity
expansion
See capacity expansion.
Array
Configuration
Utility (ACU)
A configuration utility useful both for novices and for experienced RAID users.
Array Diagnostic
Utility (ADU)
A diagnostic tool that collects comprehensive information about the array controllers in a system
and lists any problems detected.
Auto-Reliability Monitoring (ARM)
Also known as surface analysis. A fault management feature that scans physical disks for bad
sectors. Data in the faulty sectors remaps onto good sectors. Also checks parity data consistency
for disks in RAID 5 or RAID ADG configurations. Operates as a background process.
Automatic Data
Recovery
A process that automatically reconstructs data from a failed disk and writes it onto a replacement
disk. Automatic Data Recovery time depends on several factors, but HP recommends that you
allow at least 15 minutes per gigabyte. Also known as rebuild.
cache A high-speed memory component, used to store data temporarily for rapid access.
capacity
expansion
The addition of physical disks to a pre-existing disk array, and redistribution of existing logical
drives and data over the enlarged array. The size of the logical drives does not change. Also
known as array capacity expansion.
capacity
extension
The enlargement of a logical drive without disruption of data. There must be free space on the
array before capacity extension can occur. If necessary, create free space by deleting a logical
drive or by carrying out a capacity expansion. Also known as logical drive capacity extension.
CISS Command Interface for SCSI-3 Support Specification.
controller
duplexing
A type of fault tolerance that requires two Smart Array Series controllers. Each controller has
its own set of disks, and the disk sets have identical data. When one controller fails, the other
automatically takes over the servicing of requests. Controller duplexing can be done with LVM
MirrorDisk/UX.
data guarding See RAID.
data striping Writing data to logical drives in interleaved chunks (by byte or by sector). Data striping improves
system performance.
drive mirroring See RAID.
Error Correction
and Checking
(ECC) memory
A type of memory that checks and corrects single-bit or multi-bit memory errors (depending
on configuration) without causing the server to halt or to corrupt data.
fault tolerance The ability of a server to recover from hardware problems without interrupting server
performance or corrupting data. Hardware RAID is most commonly used, but there are other
types of fault tolerance, including controller duplexing and software-based RAID.
flashing Updating the flash memory on a system. Flash memory is nonvolatile memory used to hold
control code such as BIOS information. Flash memory is very fast because it can be rewritten
block by block, rather than byte by byte.
hot spare See online spare.
interim data
recovery
If a disk fails in RAID 1, 1+0, 5 or ADG, the system still processes I/O requests, but at a reduced
performance level.
logical drive A group of physical disks, or part of a group, that behaves as one storage unit. Each constituent
physical disk contributes the same storage volume to the total volume of the logical drive. A
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