2 RAID technology overview

This chapter defines the terms used in this guide and describes the RAID technologies supported by select HP Business computers.

RAID terminology

Some of the terms in the following table have a broader meaning, but they are defined in relation to the RAID implementation described in this guide.

Term

Definition

 

 

Fault tolerance

The ability of the computer to continue to operate if one drive fails. Fault tolerance is

 

often used interchangeably with reliability, but the two terms are different.

 

 

HDD

One physical hard disk drive in the RAID array.

 

 

Option ROM

A software module inside the system's BIOS that provides extended support for a

 

particular piece of hardware. The RAID option ROM provides boot support for RAID

 

volumes as well as a user interface for managing and configuring the system's RAID

 

volumes.

 

 

Primary drive

The main internal HDD in the computer.

 

 

RAID array

The physical drives that appear as one logical drive to the operating system.

 

 

RAID migration

The change of data from a non-RAID to RAID configuration. “RAID level migration,” or

 

the change of data from one RAID level to another, is not supported.

 

 

RAID volume

A fixed amount of space across a RAID array that appears as a single HDD to the

 

operating system.

 

 

Recovery drive

The hard drive that is the designated mirror (copy of the primary) drive in a RAID 1 and

 

Recovery volume.

 

 

Reliability

The likelihood—over a period of time—that a HDD can be expected to operate without

 

failure, also known as mean time before failure (MTBF).

 

 

Stripe

The set of data on a single hard drive in a RAID volume.

 

 

Striping

The distribution of data over multiple disk drives to improve read/write performance.

 

 

2 Chapter 2 RAID technology overview