Specifications

30 Implementing UPS Configurations with Microsoft Cluster Server
• The IBM Netfinity EXP15 storage expansion enclosure (3520) has an
electrical input between approximately 0.06 kVA and 0.39 kVA from two power
supplies. (Reference: IBM Netfinity EXP15 Storage Expansion Unit Hardware
Maintenance Manual.)
• The electrical input of an IBM Fibre Channel RAID Unit (3526) is similar to an
EXP15. (Reference: IBM Netfinity Fibre Channel Hardware Maintenance
Manual.) The requirement of the IBM Fibre Channel Hub (3523) is
approximately 0.2 kVA.
The electrical requirements depend on the configuration details of the devices
(for example, the number of processor or PCI adapters). More adapters in an IBM
Netfinity cause more electrical input. See http://www.pc.ibm.com/support/ for
details.
Additional components that have to be protected are network hubs or switches for
client access to the cluster. Approximately 0.6 kVA are used in the following
calculation.
Table 10. Total electrical input calculation
Our estimated shutdown time is 600 seconds. We added 60 seconds for risks
such as battery aging, so for a solution with one UPS, we need a run time of
660 seconds with 8.0 kVA. For solutions with two UPS units, we need this run
time with 4.0 kVA per unit.
As we see in Chapter 2, “APC hardware and software background” on page 3,
only the APC Symmetra can provide an output of 8 kVA, leaving it the only choice
for single UPS solutions. For example, in the Symmetra run time chart, look on
the line “8kVA” for a run time of at least 11 minutes. We see that we need
four batteries.
For solutions with two UPS units, the SU5000 is a good choice to provide the
output of 4 kVA. In the SU5000 run-time chart, notice that the estimated run time
with 4 kVA is 8 minutes only. Therefore, in a production environment, the SU5000
is not recommended, and a larger UPS is needed. In our test environment we
decided to use only one EXP15, giving us a run time of 11 minutes.
3.1.3 Recovery
We don’t recommend automatic recovery after a power failure for several
reasons:
• In a data center, a lot of services relay on each other. For example, connection
to a domain controller is needed to start the cluster service. This requires not
only a PDC or BDC, but also stable network connections. Therefore, an
Component Load Number Total
IBM Netfinity 8500R (8681) 2.1 kVA 2 4.2 kVA
IBM Netfinity Fibre Channel Hub (3523) 0.2 kVA 2 0.4 kVA
IBM Netfinity Fibre Channel RAID Unit (3526) 0.4 kVA 1 0.4 kVA
IBM Netfinity EXP15 Storage Expansion Unit (3520) 0.4 kVA 6 2.4 kVA
Network devices 0.6 kVA 1 0.6 kVA
8.0 kVA