Description

This article explains why the standby Routing Engine (RE) may not be ready to take over from the primary Routing Engine, and why the " error: Standby is not synchronizing " error message is output when the master switch check command is executed on the MX Series routers. It also provides a solution to resolve the issue.

 

Symptoms

The following error and message are output: 

labroot@MX> request chassis routing-engine master switch check   
error: Standby is not synchronizing

labroot@MX> show system switchover 
Graceful switchover: On
Configuration database: Ready
Kernel database: Ready
Switchover Status: Not Ready

 

Solution

This issue is seen in Junos OS 17.1 and later releases. Before Junos OS release 17.1, the database (Berkeley DB) that was used for sync did not have a memory check between the REs. From Junos OS 17.1, we have moved from Berkeley DB to Shared Memory where both the REs must have the same amount of RAM in order for replication to work. 

labroot@MX> show chassis routing-engine 
Routing Engine status:
  Slot 0:
    Current state                  Master
    Election priority              Master
    Temperature                 43 degrees C / 109 degrees F
    CPU temperature             41 degrees C / 105 degrees F
    DRAM                      16329 MB (16384 MB installed)            >>>>>>>> 16GB
    Memory utilization          10 percent
    5 sec CPU utilization:
      User                       0 percent
      Background                 0 percent
      Kernel                     1 percent
      Interrupt                  0 percent
      Idle                      98 percent
    1 min CPU utilization:
      User                       0 percent
      Background                 0 percent
      Kernel                     1 percent
      Interrupt                  0 percent
      Idle                      98 percent
    5 min CPU utilization:
      User                       0 percent
      Background                 0 percent
      Kernel                     1 percent
      Interrupt                  0 percent
      Idle                      98 percent
    15 min CPU utilization:
      User                       0 percent
      Background                 0 percent
      Kernel                     1 percent
      Interrupt                  0 percent
      Idle                      94 percent
    Model                          RE-S-1800x4
    Serial ID                      XX
    Start time                     2018-12-04 05:19:44 EET
    Uptime                         50 minutes, 7 seconds
    Last reboot reason             Router rebooted after a normal shutdown.
    Load averages:                 1 minute   5 minute  15 minute
                                       0.51       0.34       0.27
Routing Engine status:
  Slot 1:
    Current state                  Backup
    Election priority              Backup
    Temperature                 42 degrees C / 107 degrees F
    CPU temperature             41 degrees C / 105 degrees F
    DRAM                      32713 MB (32768 MB installed)                >>>>>>>> 32GB
    Memory utilization           5 percent
    5 sec CPU utilization:
      User                       0 percent
      Background                 0 percent
      Kernel                     0 percent
      Interrupt                  0 percent
      Idle                      99 percent
    Model                          RE-S-1800x4
    Serial ID                      XX
    Start time                     2018-12-04 05:19:33 EET
    Uptime                         50 minutes, 9 seconds
    Last reboot reason             Router rebooted after a normal shutdown.
    Load averages:                 1 minute   5 minute  15 minute
                                       0.17       0.21       0.17

 

To avoid this issue, both REs should have the same amount of RAM.

 

Modification History

2021-04-07: Updated the article terminology to align with Juniper's Inclusion & Diversity initiatives