Table of Contents
Advertisement
Galaxy A16F-R2422 Installation and Hardware Reference Manual
•
•
The A16F-R2422 supports the three topologies discussed above.
4.2.3 Host-side Topologies
The primary concern for configuring host-side topologies is to avoid points
of failure. It is therefore recommended that the host side be connected to at
least two (2) HBAs. It is also preferable to connect the FC RAID
subsystems to the host computer(s) through either a Fibre Channel hub or a
Fibre switch.
To create dual-redundant data paths on the host side, it is necessary for
third-party failover software to be installed on the host computer.
4.2.4 Redundant Controller Modes
Two (2) different redundant controller modes are supported: the
active/standby and the active/active mode.
♦ Active/standby: If this redundant controller mode is employed then
one controller (the Primary Controller) does all the work while the
other controller (the Secondary Controller) waits for the Primary to
fail. If the Primary Controller fails the Secondary Controller will take
over the operation of the RAID subsystem.
♦ Active/active: This mode allows the workload to be shared between
the two controllers. This increases the system operating speed and
allows the full potential of both controllers to be exploited. If one
controller fails, the second controller will take over the entire
workload.
4.2.5 Internal Connections
The two (2) controllers are connected to each other internally through the
backplane board. This enables the two (2) controllers to synchronize their
caches and distribute the workload. When the internal hub is turned on by
the DIP switch on the subsystem rear panel, the two (2) host channels are
connected internally to both controllers via the backplane board. This
enables the correct distribution of load traffic.
4-4
FC-AL: This is the most common topology currently in use. Fibre
Channel devices are all connected in a loop. Each device is
assigned an arbitrated loop physical address (AL_PA). The FC-AL
supports 124 devices in a single loop.
Fabric: The Fibre Channel fabric topology supports up to 224
devices. This topology allows many devices to communicate at the
same time. A Fibre switch is required to implement this topology.
NOTE:
Subsystem Connection and Operation
Advertisement
Table of Contents
