APC AP9606 Specifications download pdf (Page 59)

Chapter 3. UPS configurations for cluster 51

8. Select PowerChute PLUS Started.

Clear the Run Command File checkbox.

We strongly recommend that you do not start the cluster automatically. An

administrator has to evaluate the situation and take the required

measurements. Besides, it is mandatory to start the systems in a data center

in a certain order (PDC, BDC, databases, etc.). Usually the MSCS is the last

component to start.

3.3 Solutions with double power lines

Now let’s consider the case when electric power for the cluster is provided by two

independent power lines, which happens if:

• The data center exploits two power phases.

• The cluster is a long-distance configuration in two different data centers.

In contrast to the case of a single power line, now there are three possible failure

scenarios:

1. One power line is working properly and the other one is failing.

2. Both power lines are failing at the same time.

3. One power line is failing and the second power line fails a short period of time

later (when actions triggered by the first failure are not completed).

There are several possibilities for power cabling, but in all cases, power cabling

for shared storage equipment needs special attention. As described in Storage

power cabling on page 2, the wrong order of shared storage component failures

may destroy RAID arrays. Thus we have to ensure that all storage components

will lose power at the same moment. However, the UPS units may fail

independently. Thus we strongly recommend that you dual-attach all storage

components to both UPS units via separate power cords.

3.3.1 Solution with multiple UPS units and Redundant Switch

Using the APC Redundant Switch (see 2.3.3, “Redundant Switch” on page 16),

you can attach a server redundantly to two power lines. Failure of one power line

is hidden completely.

Because the Redundant Switch can provide a maximum output of 3 kVA, this

solution can be used only for clusters with a total power consumption of less

than 6 kVA.

Note

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APC AP9606 Specifications Page 59