Description

This article provides information on how to run the request support information command without causing high CPU utilization.

The request support information command executes various commands from the CLI (command line interface) and the VTY (virtual teletype CLI).

For more information on the request support information command, consult this document:

request support information

Symptoms

The CPU becomes busy after the request support information | no more command is executed via SSH or Telnet.

As a result, control packets can be dropped, impacting traffic.

If you have a large routing table or configuration, the possibility of encountering this issue can increase.

Solution

In the example below, the output of the run show chassis routing-engine command reveals that available CPU usage was 64% before the command was executed, but was reduced to 0% after the command was executed.

CPU Utilization BEFORE executing run support information command 

root@EX4200# run show chassis routing-engine
Routing Engine status:
  Slot 2:
    Current state                  Master
    Temperature                 40 degrees C / 104 degrees F
    CPU temperature             40 degrees C / 104 degrees F
    DRAM                      1024
    Memory utilization          61 percent
    CPU utilization:
      User                      19 percent
      Background                 0 percent
      Kernel                    16 percent
      Interrupt                  0 percent
     Idle                  64 percent
    Model                          EX4200-48PX,48 POE+
    Serial ID                      FP0211447333
    Start time                     2014-07-03 09:15:12 JST
    Uptime                         14 days, 3 hours, 11 minutes, 2 seconds
    Last reboot reason             Router rebooted after a normal shutdown.
    Load averages:                 1 minute   5 minute  15 minute
                                       0.88       2.74       2.39

CPU Utilization AFTER executing run support information command 

root@EX4200# run show chassis routing-engine
Routing Engine status:
  Slot 2:
    Current state                  Master
    Temperature                 37 degrees C / 98 degrees F
    CPU temperature             37 degrees C / 98 degrees F
    DRAM                      1024
    Memory utilization          62 percent
    CPU utilization:
      User                      68 percent
      Background                 0 percent
      Kernel                    32 percent
      Interrupt                  1 percent
     Idle                   0 percent     
    Model                          EX4200-48PX,48 POE+
    Serial ID                      FP0211447333
    Start time                     2014-07-03 09:15:12 JST
    Uptime                         14 days, 3 hours, 15 minutes, 54 seconds
    Last reboot reason             Router rebooted after a normal shutdown.
    Load averages:                 1 minute   5 minute  15 minute
                                       4.63       3.84       2.38

We recommend that you DO NOT EXECUTE the request support information command with the no-more option on a terminal window, especially when connecting to the EX via SSH or Telnet.

Instead, execute the request support information command with the save option and save the output to the /var/log/ directory, as in the following example: 

root@EX4200> request support information | save /var/log/RSI-hostname_YYYY-MM-DD.txt

For more information on the pipe ( | ) option with the save command, consult this document: