Chapter 3. IBM System Storage DS3500 Storage System planning tasks 33
second zone from HBA port 2 of the host to controller A and Controller B through port 2 of the
controllers.
With this configuration, if a single path has a fault another path can be used to access the
devices without the need of a controller failover.
3.1.2 Zoning considerations for Enhanced Remote Mirroring
The Enhanced Remote Mirroring (ERM) can only be connected through a Fibre Channel (FC)
connection, which must be dedicated for data replication between the subsystems. The ports
used for ERM cannot be used to send or receive I/Os from any host. These requirements are
addressed by defining SAN zoning. There must be two zones defined for the ERM network,
one for controller A and one for controller B. Any zones defined must separate the host ports
from the storage system mirroring ports, and also separate the mirroring ports between the
controllers.
When using ERM, you must create two additional zones:
򐂰 The first zone contains the ERM source DS3500 controller A and ERM target DS3500
controller A.
򐂰 The second zone contains the ERM source DS3500 controller B and ERM target DS3500
controller B.
ERM is detailed further in IBM Midrange System Storage Copy Services Guide, SG24-7822.
3.2 Planning for physical components
In this section, we review elements related to physical characteristics of an installation, such
as rack considerations, fiber cables, Fibre Channel adapters, and other elements related to
the structure of the storage system and disks, including enclosures, arrays, controller
ownership, segment size, storage partitioning, caching, hot spare drives, and Enhanced
Remote Mirroring.
3.2.1 Rack considerations
The DS3500 Storage System and possible expansions are mounted in rack enclosures.
General planning
Consider the following general planning guidelines. Determine the following:
򐂰 The size of the floor area required by the equipment:
Floor-load capacity
Space needed for expansion
Location of columns
򐂰 The power and environmental requirements
General rule: For MPIO driver solutions, create separate zones for each HBA port
connection from the host to both controllers (one zone for HBA port 1 and one zone for
HBA port 2), which isolates each initiator (HBA port) from the other.
34 IBM System Storage DS3500 Introduction and Implementation Guide
Create a floor plan to check for clearance problems. Be sure to include the following
considerations in the layout plan:
򐂰 Determine service clearances required for each rack or suite of racks.
򐂰 If the equipment is on a raised floor, determine:
The height of the raised floor
Anything that might obstruct cable routing
򐂰 If the equipment is not on a raised floor, determine:
The placement of cables to minimize obstruction
If the cable routing is indirectly between racks (such as along walls or suspended), the
amount of additional cable needed
Cleanliness of floors, so that the fan units will not attract foreign material such as dust
or carpet fibers
򐂰 Determine the location of:
Power receptacles
Air conditioning equipment, placement of grilles, and controls
File cabinets, desks, and other office equipment
Room emergency power-off controls
All entrances, exits, windows, columns, and pillars
Fire control systems
򐂰 Check access routes for potential clearance problems through doorways and passage
ways, around corners, and in elevators for racks and additional hardware that will require
installation.
򐂰 Store all flammable spare materials in properly designed and protected areas.
Rack layout
To be sure that you have enough space for the racks, create a floor plan before installing the
racks. You might need to prepare and analyze several layouts before choosing the final plan.
If you are installing the racks in two or more stages, prepare a separate layout for each stage.
The following considerations apply when you make a layout:
򐂰 The flow of work and personnel within the area
򐂰 Operator access to units, as required
򐂰 If the rack is on a raised floor, determine:
The need for adequate cooling and ventilation
򐂰 If the rack is not on a raised floor, determine:
The maximum cable lengths
The need for cable guards, ramps, and so on to protect equipment and personnel
򐂰 Location of any planned safety equipment
򐂰 Future expansion
Review the final layout to ensure that cable lengths are not too long and that the racks have
enough clearance.
Allow at least 76 cm (30 in.) of clearance in front of the controller-drive tray and 61 cm (24 in.)
behind the controller-drive tray for service clearance, ventilation, and heat dissipation.

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