IBM SAN Volume Controller 2145-CF8, Hardware Installation Manual

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12
Redundant ac-power switch 2
13
Site PDU X (C13 outlets)
14
Site PDU Y (C13 outlets)
The site PDUs X and Y (
13
and
14
) are powered from two independent power
sources.
In this example, only two redundant ac-power switch units are used, and each
power switch powers one node in each I/O group. However, for maximum
redundancy, use one redundant ac-power switch to power each node in the cluster.
Some SAN Volume Controller node types have two power supply units. Both
power supplies must be connected to the same 2145 UPS-1U, as shown by node A
and node B. The SAN Volume Controller 2145-CF8 is an example of a node that
has two power supplies. The SAN Volume Controller 2145-8A4 is an example of a
node that has a single power supply.
Uninterruptible power supply
The uninterruptible power supply protects a SAN Volume Controller node against
blackouts, brownouts, and power surges. The uninterruptible power supply
contains a power sensor to monitor the supply and a battery to provide power
until an orderly shutdown of the system can be performed.
SAN Volume Controller 2145-CF8 uses the 2145 UPS-1U.
2145 UPS-1U
A 2145 UPS-1U is used exclusively to maintain data that is held in the SAN
Volume Controller dynamic random access memory (DRAM) in the event of an
unexpected loss of external power. This use differs from the traditional
uninterruptible power supply that enables continued operation of the device that it
supplies when power is lost.
With a 2145 UPS-1U, data is saved to the internal disk of the SAN Volume
Controller node. The uninterruptible power supply units are required to power the
SAN Volume Controller nodes even when the input power source is considered
uninterruptible.
Note: The uninterruptible power supply maintains continuous SAN Volume
Controller-specific communications with its attached SAN Volume Controller
nodes. A SAN Volume Controller node cannot operate without the
uninterruptible power supply. The uninterruptible power supply must be
used in accordance with documented guidelines and procedures and must
not power any equipment other than a SAN Volume Controller node.
2145 UPS-1U configuration
A 2145 UPS-1U powers one SAN Volume Controller node.
To make the SAN Volume Controller cluster more resilient against power failure,
the 2145 UPS-1U units can be connected to the redundant ac-power switch.
If a redundant ac-power switch is not used, the two uninterruptible power
supplies that power an I/O group can be connected to different, independent
electrical power sources. In this case, if a single power source fails, only one node
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IBM System Storage SAN Volume Controller: Model 2145-CF8 Hardware Installation Guide