General

This defect addresses a memory leak in the NFM (Netflow Manager) process on Cisco Nexus 9000 switches running 10.6(2) or below versions. Under longevity conditions involving repeated flow timer changes and L3/multicast interface churn, NFM’s heap usage grows continuously and is not reclaimed. Over time this can cause significant memory pressure, potential process cores, or system instability.

Symptom

1. Gradual, monotonic increase in NFM memory usage reported by: show processes memory | include nfm 2.nfm MemUsed value significantly higher than baseline after hours/days of operation with repeated configuration churn. 3. Possible NFM core dump or unexpected restart after extended runtime (depending on environment and available memory).

Conditions

Long running system with triggers that include: 1. Configuring / unconfiguring L3 addresses and OSPF/OSPFv3/PIM/PIM6 on interfaces: 2. Periodic flaps on interfaces 4. Repeatedly tweaking of NFM RTP flow configs

Workaround

1. Avoid high-churn NFM/RTP-flow reconfiguration 2. Reduce interface flapping and protocol churn 3.Periodic device reload during a maintenance window

Further Problem Description