degraded

A redundant array (for example, a RAID 1 array) in which one or more members have failed.

 

The data is intact, but redundancy has been compromised. Any further failure would cause the

 

array to fail and result in data loss.

dirty data

Data that has been written to a cache, but which has not been flushed out to its final

 

destination.

disk

A nonremovable platter in a hard drive, or removable media used in a CD drive, floppy disk

 

drive, or Zip drive. See also disk ID, drive, and hard disk, hard drive.

disk ID

Unique disk identifier that consists of the channel number, ID, and LUN (channel:ID:LUN), for

 

example, 1:04:0. See also channel.

drive

Device used for storing data. May contain one or more removable or nonremovable, writable,

 

or read-only media. See also hard disk, hard drive.

drive LED

Indicator light that illuminates during read or write operations.

event

Notification or alert from the system, indicating that a change has occurred.

event log

File used to maintain information about prior controller activities or errors.

event notification

Process for transmitting events.

failed

State of a nonredundant array that has suffered a single drive failure, or a redundant array

 

that has suffered multiple drive failures. A failed array is inaccessible and data is lost.

failed partition

A partition that is no longer usable by an array because it is either logically bad and therefore

 

no longer needed, or physically damaged.

failover drive

See hotspare.

fault-tolerant array

Refers to an array that can continue to function after a disk drive failure without loss of data.

 

See also redundant.

foreign disk

Disk that has previously been initialized on another SATA RAID controller. The RAID signature

 

on the disk allows the controller to identify whether or not the disk was initialized on the

 

controller to which it is currently connected.

free space/partition

See available space/partition.

hard disk, hard

Basic unit of nonvolatile, nonremovable, magnetic storage media. See also drive.

drive

 

hot plug, hot swap

To remove a component from a system and install a new component while the power is on

 

and the system is running.

hotspare

A hard drive that is present as an array member, but which is not used in day-to-day data

 

storage. Instead, it is reserved for use as an automatic replacement drive if any of the other

 

drives in the array fail. There are two types of hotspares: Global hotspares protect every array

 

that they have enough capacity to protect, while dedicated hotspares protect only the array to

 

which they are assigned.

Glossary 22