Table of Contents
Advertisement
Power supply redundancy
There are different vendors that can vary slightly in the terminology when describing power
supply unit (PSU) redundancy. In general, 'N' is the minimum number of PSUs required to
keep the server operational, in this case, to keep the populated IBM Flex System Enterprise
Chassis operational. The term 'N+1' is the minimum number of PSUs plus one. It is not the
best option for redundancy, it is the equivalent of a "hot spare" and will protect against PSU
failure only.
The minimum number of PSUs required to keep the server or chassis operational duplicated
or doubled is referred to as 'N+N'. The PSUs are fully redundant where there will be an even
number for minimum 'N+N' support.
An IBM Flex System Enterprise Chassis would typically be connected to at least two power
distribution units (PDU) in a computer room with the PSUs connected evenly across the
PDUs. With 'N+N' redundancy the IBM Flex System Enterprise Chassis in this configuration
is also protected against PDU failure within the computer room.
1.3.2 Fan modules and cooling
The Enterprise Chassis supports up to ten hot pluggable fan modules consisting of two
40 mm fan modules and eight 80 mm fan modules.
Highlights
A chassis can operate with a minimum of six hot-swap fan modules installed, consisting of
four 80 mm fan modules and two 40 mm fan modules. The fan modules plug into the chassis
and connect to the fan distribution cards. The 80 mm fan modules can be added as required
to support chassis cooling requirements.
The two 40 mm fan modules in fan bays 5 and 10 (top two) distribute airflow to the I/O
modules and chassis management modules. These modules ship pre installed in the chassis.
Each 40 mm fan module contains two 40 mm fans internally, side by side.
The 80 mm fan modules distribute airflow to the compute nodes through the chassis from
front to rear. Each 80 mm fan module contains two 80 mm fan modules, back to back at each
end of the module, which are counter rotating.
Both fan modules have an EMC (electromagnetic compatibility) mesh screen on the rear
internal face of the module. The design of this also has an additional benefit for the airflow, by
providing a laminar flow through the screen, which reduces turbulence of the exhaust air and
improves the efficiency of the overall fan assembly. Laminar flow is a smooth flow of air,
sometimes called streamline flow. The opposite of a laminar flow is a turbulent flow. The
design of the whole fan assembly, the fan blade design, the distance between and size of the
fan modules together with the EMC mesh screen ensures a highly efficient fan design that
provides the best cooling for lowest energy input.
The minimum number of 80 mm fan modules is four. The maximum number of 80 mm fan
modules that can be installed is eight. When the modules are ordered as an option, they are
supplied as a pair.
14
IBM Flex System V7000 Storage Node Introduction and Implementation Guide
Advertisement
Table of Contents
