Chapter 2. RAID Array Controller

Stripesets (RAID 0) combine disk drives in serial to increase transfer or re- quests rates

Mirrorsets (RAID 1) combine disk drives in parallel to provide a highly reli- able storage unit

RAID 4 provides striping with a fixed parity drive

RAIDsets (RAID 5) combine disk drives in serial - just like stripesets - but also store parity data to ensure high reliability

Stripe mirrorsets (RAID 0 + 1) combine mirrorsets in serial to provide the highest throughput and availability of any storage unit

2.3Controller Reset and LED Indicators

Figure 2–4 illustrates the front panel of the controller. All LEDs are numbered from left to right. The reset button (LED 0) flashes green about once every sec- ond (heartbeat) to indicate that the controller is operating normally. LEDs 1 through 4-display host and disk channel activity (amber). LED 5 (normally off) comes on red during a controller failure. The LED/Reset switch interface is de- fined in Table 2–1.

Table 2–1 LED/Reset Switch Interface

LED #

0

1

2

3

4

5

Name

Heart Beat/LED Controller Reset Switch (green)

Host Channel 0 Activity LED (amber)

Host Channel 1 Activity LED (amber)

Disk Channel 0 Activity LED (amber)

Disk Channel 1 Activity LED (amber)

Fault LED (red)

EK–SMCPQ–UG. C01

2–5

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Compaq 3000 manual Controller Reset and LED Indicators, LED/Reset Switch Interface