AHCI and RAID on HP Compaq Elite 8000, 8100, and 8200 Business PCs

Basic RAID Types

This section provides a brief explanation of the supported RAID configurations for

HP Elite 8000-series Business PCs.

RAID 0 with two hard drives (Striped)

Even though HP supports RAID 0, it is not the recommended configuration for

business PC users. Lack of redundancy causes less than half the reliability of a

single hard drive system since the Mean Time Between Failure (MTBF) of RAID 0 is

equal to the MTBF of an individual drive, divided by the number of drives.

Table 3. RAID 0 with two hard drives (Striped)

First Disk Second Disk

Data Segment 1 Data Segment 2

Data Segment 3 Data Segment 4

Data Segment 5 Data Segment 6

Data Segment 7 Data Segment 8

Data Segment 9 Data Segment 10

Data Segment 11 Data Segment 12

Data Segment 13 Data Segment 14

Data Segment 15 Data Segment 16

In the previous table, each “Data Segment n” represents a group of data, known as

a strip. In this case, each row represents a stripe. RAID 0 represented in the table

above shows how information is segmented, made into chunks or strips, and stored

across the stripes of the hard drive members of this RAID volume.

To better illustrate the concept of RAID 0 and striping, Figure 1 shows how a

sequence of data “ABCD...” is stored in a RAID 0 mode. In this example, each

letter represents a segment or strip. The graphic shows how the various pieces of

the information go to different hard drives. If any segment of RAID 0 fails, all

information from all members is lost.