Logging of Event Notifications

Arista switches log Event Notifications using the Syslog protocol. By default, EOS logs the event notifications internally to the folder, /var/log/messages but can also be displayed on the console or logged to an external server. Configure severity levels and log message destinations using the CLI, and configure individual processes and protocols to adjust or limit the messages from them. Use the show logging command to view details of the current logging configuration.

For a full list of Syslog messages, visit the Arista website.

Managing TCAM Capacity Warnings

Strata chipsets, present in the 7010, 7050X, 7060X, 7250X, 7260X, and 7300X series switches, provide event logging for the hardware capacity of TCAM tables on a per-slice basis, and trigger a capacity warning by default whenever any TCAM slice exceeds 90% capacity. As a result, default TCAM logging can generate high levels of syslog messages on these platforms. The hardware capacity alert table command can adjust the capacity levels for the warnings above the 90% default. In that case, this adjustment can be made per TCAM resource and per slice. The command can also disable TCAM hardware capacity messages at the level Warning and below for a given slice. To disable messages, set the threshold to 0 or use the no version of the command.

Examples

  • This command reduces hardware capacity Syslog warnings by increasing the capacity threshold to 99% for EFP table monitoring in slice 2. 
    switch(config)# hardware capacity alert table EFP feature Slice-2 threshold 99

  • This command reduces messages by disabling hardware capacity Syslog warnings entirely for the IFP table in slice 5. 
    switch(config)# hardware capacity alert table IFP feature Slice-5 threshold 0

  • This command reduces messages by disabling hardware capacity Syslog warnings entirely for the VFP table in all slices. 
    switch(config)# no hardware capacity alert table VFP

Note:

Hardware capacity messages are user-configurable only at or below the “Warning” level. When depleting TCAM management software, it always sends “Error” messages to Syslog and affected features when all TCAM resources are used.

Layer 2 MAC Learn Failure Detection

A hash collision occurs when two or more distinct pieces of data map to the same entry or slot in the hardware table. It can happen when the hash function used to calculate the index for a MAC address results in the already occupied index and causes a failure of inserting the later MAC address to the hardware table.

Configuring Layer 2 MAC Learn Failure Detection

Use the following commands to enable system logging of MAC Learn Failures on the switch:

switch(config)# platform trident hardware mac-address-table collision-tracking

Use the no version of the command to disable the feature:

switch(config)# no platform trident hardware mac-address-table collision-tracking

Displaying Layer MAC Learn Failure Information

Use the following command to display missing MAC addresses in the hardware table:

switch# show platform trident l2 hardware mac-address-table missing
   Vlan  |   Mac Address         |   Present in SW?   |   Present in HW   | Missing in HW |
---------|-----------------------|--------------------|-------------------|---------------|
   2141  |   00:00:04:00:00:09   |         Y          |                   | Switchcard1/0 |
---------|-----------------------|--------------------|-------------------|---------------|
   2141  |   00:00:03:00:19:0c   |         Y          |                   | Switchcard1/0 |
---------|-----------------------|--------------------|-------------------|---------------|
                
Total entries missing in software:  0                                                    
                
Total entries missing in hardware:  2                                                    
Switchcard1/0:  2

Sample Syslog Message for L2 MAC Learn Failure

%ETH---MACADDRBANKFULL: Unable to program learned dynamic host table entry for MAC address MAC address in VLAN VLAN Id due to hardware resource exhaustion.