Rackable Systems OmniStor 4900F Series, User Manual, Page: 41 / 196

Chapter 2 - Topologies and Operating Modes
Dual Port Single Host Dual Connection
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In this topology the Host I/O card switches 1, 2, and 4 are set to the “Up” position.
Switch 1 sets the bus speed mode on the Host I/O card to 2 GB/sec.
Switch 2 configures the enclosure for the Wahoo RAID Controller.
Switch 4 provides the link between the Host I/O card “H0” and “H1” ports to the
same Fibre loop.
Dual Port Single Host Dual Connection
This topology provides an entry-level RAID storage solution for dual ported host systems
with multiple paths to the storage. It offers the following advantages: an initially lower cost
system to deploy, multiple paths from host which can maximize controller bandwidth, and
it provides multiple paths for optional upstream failover. It has several disadvantages: the
Wahoo2 RAID Controller is a single point of failure, it requires two single ported HBAs or
a dual ported HBA, and if upstream path failover is implemented then additional software
is required.
Simplex Mode Logical View - Dual Port Single Host Dual Connection
In this topology the Host I/O card switches 1, 2, and 4 are set to the “Up” position.
Switch 1 sets the bus speed mode on the Host I/O card to 2 GB/sec.
Switch 2 configures the enclosure for the Wahoo2 RAID Controller.
Switch 4 provides the link between the Host I/O card “H0” and “H1” ports to the
same Fibre loop.