Chapter 3. Uninterruptible Power Supply; 2145 Ups-1U; 2145 Ups-1U Configuration - IBM 2145-8F2 Hardware Installation Manual

Chapter 3. 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 2145-8F4 and SAN Volume Controller 2145-8F2 use 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

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 supply
units 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
in the I/O group stops and the SAN Volume Controller cluster can continue to
operate although with reduced performance.
Each uninterruptible power supply must be in the same rack as the node that it
powers.
Each 2145 UPS-1U includes one power cord that connects the uninterruptible
power supply to a redundant ac-power switch, if one exists, or to a rack power
distribution unit (PDU), if one exists. The 2145 UPS-1U also includes an alternative
power cable to connect to an external power source that is specific to your
geography.
© Copyright IBM Corp. 2003, 2008
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.
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