Redundant Drive Loop Cabling Overview - IBM TotalStorage DS4300 Installation, User's, And Maintenance Manual

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Redundant drive loop cabling overview

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Loop A
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Figure 36. Redundant drive loop cabling overview
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IBM TotalStorage DS4300 Fibre Channel Storage Subsystem: Installation, User's, and Maintenance Guide
and RAID controllers. The expansion drive (or storage expansion enclosure) fibre
channel loop provides the fibre path to the hard disk drives (HDDs) that are outside
the DS4300 storage subsystem chassis. The drive fibre channel loop consists of
fibre channel HDDs and optional DS4000 EXP storage expansion enclosures, fibre
channel cables, and SFPs.
The DS4300 dual-controller storage subsystem (Model 60U/60X) supports
redundant disk-drive-loop configurations. You can build a redundant drive loop by
connecting one or more DS4000 EXP storage expansion enclosures to the
redundant RAID controllers. Then, use dual fiber-optic cables to connect one
storage expansion enclosure to another in a daisy-chain. For more information
about adding storage expansion enclosures, see "Connecting storage expansion
enclosures to the DS4300" on page 45.
The DS4300 with dual controllers storage subsystem supports one redundant drive
loop. A redundant drive loop consists of one or more storage expansion enclosures
connected to a controller using two sets of fibre channel cables. If one data path
fails, the controller uses the other data path to maintain the connection to the drive
group.
Figure 36 shows a storage subsystem containing one storage subsystem and one
redundant drive loops with four storage expansion enclosures. Each storage
expansion enclosures group uses redundant drive loops to connect to the DS4300
Storage Subsystem.
Attention: To prevent loss of storage expansion enclosure redundancy, connect
the storage expansion enclosures as shown in Figure 36.
Note: The illustrations in this document might differ slightly from the hardware.
Loop B
Storage
expansion
enclosure
group 1
Storage
Subsystem
d43nu4041