Drive-side trunking cabling
Notes:
1. The EXP5060 storage expansion enclosure requires firmware version
7.60.13.05, or higher for drive-side trunking cabling.
2. The actual improvement in throughput depends on your logical drive
configuration and workload. In addition, this cabling scheme is also
recommended because it provides additional redundancy between the storage
subsystem controllers and EXP5060 ESMs. There is no way to disable the
EXP5060 trunking cabling functionality besides not making connections to the
second set of ESM ports labeled 2A and 2B.
3. Only the EXP5060 storage expansion enclosure supports drive-side trunking.
There is no drive-side trunking support for the EXP5000/EXP810 storage
expansion enclosure.
The EXP5060 is shipped with trunking cabling functionality enabled. Trunking
cabling is the cabling scheme where the controller drive ports are connected to the
EXP5060 drive channel ports labeled 1B and 2B on both ESMs of the EXP5060.
This cabling scheme results in two connections between the storage subsystem
controller and each of the EXP5060 ESMs forming two pairs of redundant drive
loops. With two pairs of redundant drive loops, up to four drives can be accessed
concurrently in a single EXP5060 enclosure. This cabling scheme is recommended
when there is a need to maximize throughput (for large sequential read I/Os)
between the storage subsystem controllers and the drives in the EXP5060
enclosures.
In addition to making the additional Fibre Channel connections to support drive-side
trunking, consider the following before creating and using the RAID arrays to
maximize throughput.
v
Make sure that both controllers access the enclosure to use all bandwidth
provided by trunk connections.
v
Balance drives access by a controller across all available drive channels by
making sure that a controller is accessing an equal number of drives from all
drive channels.
v
Balance drives access by a controller across both ESMs in a EXP5060 storage
enclosure by ensuring that the number of drives in odd slots and even slots used
by a controller is equal.
v
Create RAID arrays so that the drives in one disk drawer can be accessed by
only one controller to avoid drive loop contention in the disk drawer. Share the
EXP5060 enclosures between controllers instead of sharing disk drawers within
an EXP5060 between controllers.
Because there are two EXP5060 ESM ports that each controller connects to, two of
the controller drive ports must be used to connect to each EXP5060 ESM. The
following cabling rules must be followed for making correct trunking cabling
connections:
v
The cabling configuration must be homogenous on a given drive channel/loop. All
point-to-point connections between each set of enclosures in a drive channel
(controller-to-ESM and ESM-to-ESM) must be cabled using either the trunking or
non-trunking cabling scheme. Having some connections in the same drive
channel/loop in a trunking scheme and some connections in a non-trunking
scheme is not supported.
v
The cabling configuration must be homogenous for the two ESMs in a given
EXP5060 enclosure. For example, if ESM A of the EXP5060 is connected using
Chapter 3. Cabling the storage subsystem
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