Galaxy GHDXS2-1430R-16F4D Installation and Hardware Reference Manual
3-4
When cabling, follow all Fibre Channel specifications. Pay attention to
signal quality and avoid electronic noise from adjacent interfaces.
The disk drives in the same logical array should have the same capacity,
but it is preferred that all the drives within the subsystem have the same
capacity.
Mixing SAS and SATA disk drives in the same enclosure is allowed.
However, including SAS and SATA disk drives in the same logical
drive is not recommended.
A spare drive (Local, Global, or Enclosure spare) should have a
capacity equal to the largest drive that it is expected to replace. If the
capacity of the spare is smaller than the capacity of the drive it is
expected to replace, then the controller will not proceed with the failed
drive rebuild.
3.2.2 Fibre Channel Topologies
The Fibre Channel standard supports separate topologies. They are Fibre
Channel Arbitrated Loop (FC-AL) and fabric switch topologies.
•
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 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.
3.2.3 Host-side Topologies
The primary concern for configuring host-side topologies is to eliminate
points of failure. It is therefore recommended that the host interfaces be
connected to at least a dual-ported host using two (2) HBAs. It is also
preferred to connect the subsystems to host computer(s) through intelligent
Fibre switches that feature zoning and fault recovery algorithms.
NOTE:
Multipathing software on the host computer(s) is necessary in order to
manage the I/O traffic through the fault-tolerant, redundant data paths to a
RAID subsystem.