Rorke Data Galaxy A16F-G2422, Руководство по установке и аппаратным средствам

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Galaxy Raid Installation and Hardware Reference Manual
4-4
Topology and Configuration Considerations
•
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
127 devices in a single loop.
•
Fabric: The fabric topology supports up to 2
24
Fibre channel
devices. This topology allows many devices to communicate at the
same time. A Fibre switch is required to implement this topology.
The GALAXY 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.
NOTE:
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 Unique Identifier
The unique identifier is a user-specified, 16-bit hexadecimal number that is
used to assign a FC port number to the active controller. Each controller is
assigned a separate hexadecimal number and the firmware then determines
which unique identifier to use. To see how to use the front panel LCD
screen or the terminal emulation program to enter the unique identifier,
please refer to the User’s Operation Manual .
4.2.5 ID/LUN Mapping
I/O load distribution is determined by the host ID/LUN mapping. Different
logical groups of drives are mapped to the LUN numbers under a host ID.
For a multi-host operation, a logical drive configuration can be mapped to
different ID/LUN combinations. In this case, the file locking mechanism is
necessary. ID/LUN mapping procedures are described fully in the User’s
Operations Manual .