Rackable Systems OMNISTOR 4000f SERIES, User Manual

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Chapter 2 - Topologies and Operating Modes
Single Bus Dual-Loop Mode
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Single Bus Dual-Loop Mode
The Single Bus Dual-Loop mode provides a basic single enclosure where the drive plane is
configured as a continuous twelve drive single bus dual-loop FC-AL JBOD configuration.
You also have the ability to add additional drives through daisy-chain enclosures, to a
maximum of 96 disk drives in a dual-loop FC-AL configuration. (A maximum of 124
devices can be achieved through soft addressing on the last two enclosures added beyond
the 96 devices. However this is not recommended.)
The jumper, (JP3) on the Disk I/O card, should be offset on one pin to enable this option.
When enabled, it also activates the internal hubs and provides a continuous FC loop to the
drives. This is the default configuration.
NOTE:
This single bus dual-loop configuration is used for the daisy-chained enclosures
that expand the drive channels in a RAID configuration.
Single Bus Dual-Loop Operating Mode Logical View
Depending on how the host or hosts are connected to this configuration will determine
whether the topology provides a dual-loop or a redundant path solution to the drive ports.
If Port 1 and Port 2 of the HBA are connected to Loop A (upper Disk I/O) and Loop B
(lower Disk I/O) respectively, volume management software is required.
Disk I/O Card
(Upper - Loop A)
Disk I/O Card
(Lower - Loop B)
D1
D2
D1
D2
PBC
PBC
PBC
PBC
Drive Slots 1 - 6
Drive Slots 7 - 12
Loop A
Loop B
Loop A
Loop B