Specifications
© IBM Copyright, 2012 Version: January 26, 2012
www.ibm.com/support/techdocs 27
Summary of Best Practices for Storage Area Networks
When installing fiber cabling, use labels on each end of the cable which provides
sufficient information to identify the appropriate connection ports. Use a logical naming
scheme to uniquely identify every cable along with its source and destination points.
Good labeling reduces potential confusion as well as easing the task of finding a
specific cable in a bundle. Cable labels should always be included as a key step for
routine change management documentation and standard operating procedures.
If zip ties are used with cables, extreme care must be utilized. If pulled too tightly, the
zip tie will damage the cable’s core and/or outer cladding. Velcro tie wraps are strongly
suggested. Do not bundle a large number of cables together. Instead, bundle a few
cables together and then combine these smaller bundles into larger groups. This
practice provides for proper support of cables yet allows for easy isolation and/or
replacement of a bad cable with minimal impact. Bundle ties should be located every 2
feet, or less, of cable run.
Depending on the maker of the fiber cabling, the proposed minimum diameter for
bending a fiber optic cable can vary significantly. Some vendors provide a simple
measurement, while other vendors state that bend diameters should not be less than
some number of cable thicknesses. In the absence of a ruler in the data center, a
simple guideline is to use the width of four fingers of one’s hand. If the diameter of a
cable bend is less than that measure, then the bend radius is likely too tight.
Good cable management involves planning within every rack, between racks, at patch
panels, in the data center and beyond. Good cable management implies a structured
and consistent approach when planning and then implementing cabling. This key
concept applies to both optical and wired media since both are likely to be co-located in
the same space. Good cable management will address concerns for the current needs
while having the flexibility to meet future needs due to technology changes, increased
port counts, increase port density or some custom requirement.
A good source of information about planning cable infrastructures can be found in the
Telecommunications Industry Association standard TIA-942 titled “Telecommunications
Infrastructure Standards for Data Centers”. Beside cabling infrastructure, this standard
also covers topics such as site space and layout, tiered reliability and environmental
considerations.