COSD (Class Of Service daemon process) uses rtsock to read/write data from kernel. If the write fails, the kernel returns an error.

The problem related to this syslog message is described in the following sections:

The COSD_RTSOCK_WRITE_FAILED message is logged each time the Class of Service process gets a failed status when attempting to write data to the kernel using the rtsock library.

When a COSD_RTSOCK_WRITE_FAILED event occurs, a message similar to the following is reported:

The cause may be due to several sources. There may be insufficient memory available in the kernel to handle the library call, memory corruption of an internal table, or an issue with the Class Of Service process handling of the message, among other reasons.

Examine the following output to help determine the cause of this message:

Look for any related events that occurred at or just before the COSD_RTSOCK_WRITE_FAILED message.

Perform these steps:

1. During a maintenance window, as it will impact transit traffic, try the following:

  • Restart the class of service process using the command: restart class-of-service
  • For more information on restarting a process, refer to Restart a Junos Software Process.
    Reboot the Routing Engine.

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