Core issue
The %EARL_NETFLOW-4-TCAM_THRLD error message indicates that the NetFlow Ternary Content Addressable Memory (TCAM) is almost full, so aggressive aging is temporarily enabled. If the NetFlow mask is changed to FULL mode, the TCAM for NetFlow could overflow due to so many NetFlow entries. This situation can be verified if the show mls netflow ip count command is issued.
The Supervisor Engine 720 checks how full the NetFlow table is every 30 seconds. The Supervisor Engine turns on aggressive aging when the table size reaches almost 90 percent. The idea behind aggressive aging is that the table is nearly full, so there are new active flows which cannot be created. Therefore, it makes sense to aggressively age-out the less active flows (or inactive flows) in the table to make space for more active flows.
The capacity for each policy feature card (PFC) NetFlow table (IPv4), for PFC3a and PFC3b, is 128,000 flows. For the PFC3bXL, the capacity is 256,000 flows.
The NetFlow usage notification feature is disabled by default. The %EARL_NETFLOW-4-TCAM_THRLD error message seen is most likely the result of service internal being present in the configuration and printed when the NetFlow usage reaches 90 percent.
The error message looks similar to
Aug 24 12:30:53: %EARL_NETFLOW-SP-4-TCAM_THRLD: Netflow TCAM threshold exceeded,
TCAM Utilization [97%]
Resolution
To prevent this problem, issue the no mls flow ip command to disable the FULL NetFlow mode.
Note: Generally, the no mls flow ip command does not affect packet forwarding because TCAM for packet forwarding and TCAM for NetFlow accounting are separate.
Error message
%EARL_NETFLOW-4-TCAM_THRLD