Cabling the switch, Cabling best practices, Cabling the – HP 3Gb SAS Switch for HP BladeSystem c-Class User Manual
Page 17: Switch
Cabling the switch
After confirming the firmware version, connect SAS cables between the switch and the external SAS
storage enclosures or tape devices.
NOTE:
The 3Gb SAS BL Switch uses SAS cables with mini-SAS universal connectors. For a list of supported
cables, see the 3Gb SAS BL Switch QuickSpecs.
Cabling best practices
•
When cabling external storage enclosures to the switch, consider which BladeSystem c-Class
server bays will need access to the storage. For example, when the 3Gb SAS BL Switch is installed
in an HP BladeSystem c7000 enclosure:
• Storage enclosures connected to switch ports 1–4 are reserved for use by server bays 1–8 in
the BladeSystem c-Class enclosure.
• Storage enclosures connected to switch ports 5–8 are reserved for use by server bays 9–16
in the BladeSystem c-Class enclosure.
For more information, see
•
In optimal or wide-port configurations with two cable connections from the storage enclosure to
the same 3Gb BL SAS Switch, ensure that both cables from storage enclosure connect to one of
the following pairs of switch ports: 1/2; 3/4; 5/6; or 7/8.
•
In high-availability, dual-domain configurations with paired switches, redundant controllers or I/O
modules, and dual-ported SAS disk drives, connect cables from the redundant modules in the
storage enclosure to the same switch port on the paired switches. For example, connect the storage
enclosure to port 2 on each switch. This parallel cabling strategy ensures easier record-keeping,
troubleshooting, and support.
•
Ensure that cabling in the back of the rack system does not interfere with system operation or
maintenance. Bind cables loosely with cable ties and route the excess out of the way, along the
side of the rack. When cables are tied together and routed down the side of the rack, system
components and indicators are easily visible and accessible.
•
Attach a label near both ends of each cable to identify the device connected to that cable. Include
the device, device name, port, or other useful information.
•
Use colored markers or labels to color-code both ends of each cable and help you visually
identify a particular cable without having to read or locate the label.
•
Use the shortest possible cable between devices. Shorter cables are easier to manage and route
along the back of the rack. In addition, shorter cables reduce the possibility of signal degradation
that can occur over longer distances.
IMPORTANT:
External storage enclosures are tested and approved for use with specific cable lengths. Before
purchasing and connecting SAS cables to external storage enclosures, check the QuickSpecs for
the device and make sure that cables do not exceed the maximum supported length.
3Gb SAS BL Switch User Guide
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