Comprehensive and Detailed Explanation From Exact Extract:
Resource is showing outdated information: If polling intervals are too long or if there is a communication problem, the hardware health resource may not update promptly, resulting in inaccurate status display.
Wrong MIB being used for polling: If SolarWinds is using an incorrect or generic MIB, it may not retrieve accurate hardware health data for the specific fan sensor, causing the status to incorrectly display as "up" even when failed.
While disabled sensors and forced thresholds may impact alerting or monitoring, they are less likely to cause this direct display inconsistency.
References:
NPM Administrator Guide: Troubleshooting Hardware Health Inaccuracies
Official SolarWinds KB: Hardware Health Sensor Status Issues

For effective network capacity planning:
Enough historical data (at least 7 days) must be available: This ensures meaningful trend and forecast analysis.
Relevant objects (nodes, interfaces, volumes) must be managed: Only managed entities are included in capacity planning calculations.
Polling every OID or updating the MIB database (A, D) is not a direct requirement for capacity planning.
Reference:
NPM Administrator Guide, "Capacity Planning Prerequisites and Requirements"

The most common cause of mismatch between bandwidth (SNMP) numbers and flow (NetFlow, sFlow, etc.) numbers is that not all network traffic is included in the flow export. SNMP bandwidth counters include all traffic traversing the interface, but NetFlow or other flow records may only represent sampled or filtered subsets, or may miss certain traffic due to export or device configuration limitations. This is a well- documented and expected difference in the SolarWinds platform.
Reference:
Network Performance Monitor Administrator Guide, "Understanding Bandwidth and Flow Discrepancies,"
"Flow data