Storage Area Networks (SAN)

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Using RDP with IBM FlashSystem to Debug Fibre Channel Optics Errors

By Ashish Jagdale posted Fri December 09, 2022 01:40 AM

What is RDP?
RDP is an FC primitive, which enables you to use the FC switch command-line interface (CLI) to monitor and debug the small form factor pluggable (SFP) optical  modules that are installed on endpoint devices.

Why is RDP relevant?
In an FC storage area network (SAN), bad optics and cabling tend to be one of the most common point of failures. This situation can result from SFP electronics wearing out over time, cables malfunctioning due to physical stress, or other issues. These component-facing issues might manifest as performance drops, loss of paths, congestion, and other issues.

In Fabric or FC SANs, it can be difficult to identify the exact item that causes such issues. An average compute node can have around 2 - 3 FC adapters, with up to four ports each. Modern SAN storage devices might have up to four quad-port FC adapters per node, which means that there are many physical ports in any SAN.
A basic illustration of how RDP commands work.

The IBM FlashSystem® family of products incorporate support to respond to these commands from version and later. With an FC switch from Brocade with FOS 7.4 and above, or Cisco with NXOS 8.x and above, you can easily use switch CLI to centrally gather information about remote port health status in detail. These details include temperature levels, error counts, alarms, and more. Which can easily be used to identify ongoing or potential issues.

More resources:
For more details with detailed description of all the CLI involved, sample outputs, and their significance, please refer to the following IBM blueprint: