NetApp AFF A700, System Documentation

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The SAS cabling rules regarding configuration rules and mini-SAS HD SAS optical cable rules described in this
guide are specific to disk shelves with IOM12 modules.
The SAS cabling rules described in this guide balance SAS cabling between the on-board SAS ports and host
bus adapter SAS ports to provide highly available storage controller configurations and meet the following
goals:
• Provide a single, easily understood universal algorithm for all SAS products and configurations
• Yield the same physical cabling when generating the Bill of Materials (BOM), followed in the factory, and in
the field
• Are verifiable by configuration-checking software and tools
• Provide maximum possible resilience to maintain availability and minimize the reliance on controller
takeovers
You should avoid deviating from the rules; deviations might reduce reliability, universality, and commonality.
Configuration rules
Disk shelves with IOM12 modules are supported in specific types of HA pair and single-
controller configurations.
• HA pair configurations must be cabled as multipath HA or quad-path HA configurations with the following
exceptions:
◦
AFF A200, AFF A220, FAS2600 series and FAS2700HA pair configurations (with external disk shelves)
can be cabled as single-path HA configurations to support connectivity to an external SAS tape backup
device.
◦
AFF A200, AFF A220, FAS2600 series and FAS2700HA pair configurations do not support quad-path
HA connectivity.
• Single-controller configurations must be cabled as multipath or quad-path configurations, with the following
exceptions:
◦
FAS2600 series single-controller configurations (with external disk shelves) can be cabled as single-
path configurations.
Because the internal storage uses single-path connectivity, ONTAP issues occasional warnings that
mixed paths are detected. To avoid these warnings, you can use single-path connectivity to the
external disk shelves. Additionally, you can use single-path connectivity when an external SAS tape
backup device is used.
◦
FAS2600 series single-controller configurations do not support quad-path connectivity.
Controller slot numbering rules
For the purpose of applying cabling rules across all supported HA pairs and single-
controller configurations, a controller slot numbering convention is used.
• For all HA pairs and single-controller configurations, the following applies:
◦
A SAS HBA in a physical PCI slot is defined as occupying PCI slot 1, 2, 3, and so on regardless of the
slot’s physical label on a controller.
For example, if SAS HBAs occupied physical PCI slots 3, 5, and 7, they would be designated as slots
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