Description

EX3400 and EX4300 use different CPU architectures because the FreeBSD versions differ. Therefore, you might see RE (routing engine) memory utilization scale differences on the two models.
 
 

Symptoms

The JunOS EX4300 platform is based on BSD6 [legacy FreeBSD] in comparison to EX2300/EX3400, which are on BDS10-12.

Below are the two FreeBSD device versions:
 
EX3400: 
> start shell
% sysctl kern.osreldate
kern.osreldate: 1100513 <<< freebsd version 11
 
EX4300: 
> start shell
% sysctl kern.osreldate
kern.osreldate: 601000 <<< freebsd version 6
------

The CPU utilization architectures are not the same between the two models due to the above FreeBSD versions. The EX3400 reports most of its memory usage as inactive, whereas EX4300 reports most of it as active. Since inactive does not count towards the memory usage as seen in ‘show chassis routing-engine, the usage looks much lower on the EX3400 in-comparison to EX4300.

Model: EX4300-48p 
-----------------------------------------------------------
System memory usage distribution:
       Total memory: 1943552 Kbytes (100%)
    Reserved memory:   38572 Kbytes ( 1       Wired memory:  145736 Kbytes ( 7%)
      Active memory: 1111152 Kbytes ( 57%) <<<<
    Inactive memory:   81460 Kbytes (  4%)
       Cache memory:  488532 Kbytes ( 25%)
        Free memory:   77428 Kbytes (  3%)
 
Memory utilization = 100 -(4+25+3)) = 68 %
(Note that memory utilization equals "100 - Inactive memory -Cache memory - Free memory")
  
> show chassis routing-engine
Routing Engine status:
  Slot 0:
    Current state                  Master
    Temperature                 44 degrees C / 111 degrees F
    CPU temperature             44 degrees C / 111 degrees F
    DRAM                      2048 MB
    Memory utilization          68 percent <<<<
-----------------------------------------------------------
 
Model: EX3400-48p
----------------------------------------------------------- 
System memory usage distribution:
       Total memory: 1991312 Kbytes (100%)
    Reserved memory:   39540 Kbytes (  1%)
       Wired memory:  196940 Kbytes (  9%)
      Active memory:   82980 Kbytes (  4%) <<<<
    Inactive memory:  944904 Kbytes ( 47%)
       Cache memory:       0 Kbytes (  0%)
            Free memory:  726948 Kbytes ( 36%)
 
Memory utilization =  100 -(47+0+36)) = 17 %
 
> show chassis routing-engine no-forwarding
Routing Engine status:
  Slot 0:
    Current state                  Master
    Temperature                 32 degrees C / 89 degrees F
    CPU temperature             32 degrees C / 89 degrees F
    DRAM                      1945 MB (2048 MB installed)
    Memory utilization          18 percent
    5 sec CPU utilization:
      User                      17 percent <<<<
----

Solution

The different memory utilization scales on the two models are the expected behavior and it does not indicate a memory issue.
 

Modification History

.

Related Information