Compaq 3000 manual Environmental, Backup Power Management, Response to Various AC Power Conditions

RAID Array 3000 Controller Shelf

2.9 Environmental

The controller incorporates a set of on board sensors to detect abnormal operat- ing conditions that may affect data safety.

2.9.1 Backup Power Management

The controller must be connected to the Uninterruptable power supply (UPS) to prevent the subsystem cache from being corrupted during unexpected losses of power. If no backup power supply is provided, the controller will remain off-line and reject all I/O requests with a status of Check Condition/Hardware Error.

During normal operation, RAID 3000 ac power is supplied from a line source through both power cords to both power supplies. Conditions of poor or no power causes the following UPS responses:

Table 2–5 Response to Various AC Power Conditions

Condition

Low line voltage

No line voltage (AC loss)

UPS low-battery warning

UPS power down

Response

UPS compensation circuit automatically increases out- put voltage, without placing load on the UPS battery.

UPS switches to the battery which supplies power to the RAID 3000 maintaining full functionality.

UPS signals RAID 3000 controller of impending power down. Caching is disabled but the RAID 3000 continues to service host requests and begins to flush cache to disk.

UPS signals RAID 3000 controller of impending power down. Subsystem discontinues host services. Cache flush is completed.

UPS shuts itself off, preventing complete battery dis- charge. All data has been written to disk.

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