Installation guide

Section 2.1:Choosing a Hardware Configuration 29
Hardware Quantity
One network crossover cable A network crossover cable connects a network interface on
one cluster system to a network interface on the other system,
creating a point-to-point Ethernet heartbeat channel.
Two RPS-10 power switches Power switches enable each cluster system to power-cycle the
other system before restarting its services. The power cable for
each cluster system is connected to its own power switch.
Three null modem cables Null modem cables connect a serial port on each cluster
system to the power switch that provides power to the
other cluster system. This connection enables each cluster
system to power-cycle the other system.
A null modem cable connects a serial port on one cluster
system to a corresponding serial port on the other system,
creating a point-to-point serial heartbeat channel.
FlashDisk RAID Disk Array
with dual controllers
Dual RAID controllers protect against disk and controller failure.
The RAID controllers provide simultaneous access to all the
logical units on the host ports.
Two HD68 SCSI cables HD68 cables connect each host bus adapter to a RAID enclosure
"in" port, creating two single-initiator SCSI buses.
Two terminators Terminators connected to each "out" port on the RAID enclosure
terminate both single-initiator SCSI buses.
Redundant UPS Systems UPS systems provide a highly-available source of power. The
power cables for the power switches and the RAID enclosure are
connected to two UPS systems.
Figure 2–1, No-Single-Point-Of-Failure Configuration Example shows an example of a no-single-
point-of-failure hardware configuration that includes the hardware described in the previous table,
two single-initiator SCSI buses, and power switches to guarantee data integrity under all error condi-
tions. A "T" enclosed in a circle represents a SCSI terminator.