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Chapter 7

Starting the DPU

Startup States

Refer to this chapter to learn how to:

• Start a standalone DPU

• Start DPUs in a backup pair

• Replace a DPU in a backup pair

When a DPU boots, it checks for a valid configuration and database existing

in its flash memory and proceeds to load it if one is found. The DPU then

listens over the backup link to see if another DPU is active and in control

before it operates on the loaded configuration.

If no backup DPU is present (no backup link communications, no Network

A/B communications, no active pulses on the backup link cable) then, the

DPU continues to operate with its loaded configuration and intended

operation as either a standalone DPU or a backup DPU. It becomes the

Active DPU since no other DPU is in control.

If a backup DPU is present then, this DPU listens to the other DPU over the

backup link as to its current operation as Standalone or Redundant DPU. If

the other active DPU is set as a Redundant DPU (NOT Standalone) then, this

inactive DPU will erase its configuration/database and proceed to gather

configuration and database information, from the Active DPU, over the

backup link. This DPU will move from an empty state to a warming state and

then to a hot standby state and become ready to assume control when

commanded to take over.

Demanding a Blank Startup

When a DPU is first placed in service it is advisable to clear any previous

configuration data that may remain in its flash memory. To do this, before

applying power to the DPU, set the Mode switch, on the DPU Chassis, to

‘B’. After the DPU has gone through its startup sequence as described in

"Starting a Standalone DPU," be sure to set the Mode switch back to ‘F’ to

prevent future Cold (no database) startups.

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Adaptec 1542B - AHA Storage Controller Fast SCSI 10 MBps Specifiche Pagina 35