Dear fellow Juniper-users,

I recently replaced a SRX240HE2 with a SRX340, using the same configuration in the same environment.

All works fine, I have no alarms, but I do see a rather high CPU temperature of over 70C.

The SRX240HE2 used to have CPU temps of around 44C, as you can see the temp of the routing engines is the same.

I can't find a temperature threshold for the CPU itself (only for the RE).

The CPU load is very low (Today it hasn't been over 10,4%) and the fan speed is normal.

Is this normal behaviour for a SRX340, having CPU temperatures far above that of a SRX240, or could it be a hardware/manufacturing problem?

Output SRX340: ====================================================================================

> show chassis routing-engine
Routing Engine status:
    Temperature                 44 degrees C / 111 degrees F
    CPU temperature             72 degrees C / 161 degrees F
    Total memory              4096 MB Max  1188 MB used ( 29 percent)
      Control plane memory    2624 MB Max   682 MB used ( 26 percent)
      Data plane memory       1472 MB Max   486 MB used ( 33 percent)
    5 sec CPU utilization:
      User                       6 percent
      Background                 0 percent
      Kernel                     5 percent
      Interrupt                  0 percent
      Idle                      89 percent
    Model                          RE-SRX340
    Serial ID                     
    Start time                    
    Uptime                        
    Last reboot reason            
    Load averages:                 1 minute   5 minute  15 minute
                                       0.03       0.09       0.08

> show chassis environment
Class Item                           Status     Measurement
Temp  Routing Engine                 OK         44 degrees C / 111 degrees F
      Routing Engine CPU             OK         72 degrees C / 161 degrees F
Fans  SRX340 Chassis fan 0           OK         Spinning at normal speed
      SRX340 Chassis fan 1           OK         Spinning at normal speed
      SRX340 Chassis fan 2           OK         Spinning at normal speed
      SRX340 Chassis fan 3           OK         Spinning at normal speed
Power Power Supply 0                 OK        

> show chassis temperature-thresholds
                           Fan speed      Yellow alarm      Red alarm      Fire Shutdown
                          (degrees C)      (degrees C)     (degrees C)      (degrees C)
Item                     Normal  High   Normal  Bad fan   Normal  Bad fan     Normal
Chassis default              35    45       50       40       75       65      100
Routing Engine               35    45       50       40       75       65      100

> show system software
Information for junos:

Comment:
JUNOS Software Release [15.1X49-D70.3]

====================================================================================

Output SRX240HE2: ====================================================================================

> show chassis routing-engine
Routing Engine status:
    Temperature                 45 degrees C / 113 degrees F
    CPU temperature             44 degrees C / 111 degrees F
    Total memory              2048 MB Max  1208 MB used ( 59 percent)
      Control plane memory    1072 MB Max   504 MB used ( 47 percent)
      Data plane memory        976 MB Max   712 MB used ( 73 percent)
    CPU utilization:
      User                       6 percent
      Background                 0 percent
      Kernel                     3 percent
      Interrupt                  0 percent
      Idle                      91 percent
    Model                          RE-SRX240H2
    Serial ID                     
    Start time                    
    Uptime                        
    Last reboot reason            
    Load averages:                 1 minute   5 minute  15 minute
                                       0.02       0.05       0.05

pbelt@pbelt-router> show chassis environment
Class Item                           Status     Measurement
Temp  Routing Engine                 OK         45 degrees C / 113 degrees F
      Routing Engine CPU             OK         44 degrees C / 111 degrees F
Fans  SRX240 PowerSupply fan 1       OK         Spinning at normal speed
      SRX240 PowerSupply fan 2       OK         Spinning at normal speed
      SRX240 CPU fan 1               OK         Spinning at normal speed
      SRX240 CPU fan 2               OK         Spinning at normal speed
      SRX240 IO  fan 1               OK         Spinning at normal speed
      SRX240 IO  fan 2               OK         Spinning at normal speed
Power Power Supply 0                 OK        

> show chassis temperature-thresholds
                           Fan speed      Yellow alarm      Red alarm      Fire Shutdown
                          (degrees C)      (degrees C)     (degrees C)      (degrees C)
Item                     Normal  High   Normal  Bad fan   Normal  Bad fan     Normal
Chassis default              35    45       50       40       75       65      100
Routing Engine               35    45       50       40       75       65      100

> show system software
Information for junos:

Comment:
JUNOS Software Release [12.3X48-D35.7]

====================================================================================

Hi Folks,

If you are replacing a SRX240 with a SRX340 in the same rack; i would suggest to double check the environment conditions. Since the air-flow pattern differs for both the boxes as below.

Can you please check if there is proper allowance in the front/back of the SRX340 chassis as the fans draw air through vents on the front of the chassis and exhaust the air through the back of the chassis.

SRX240 Services Gateway Cooling System

The fans draw air from the right side of the chassis (when the chassis is viewed from the front) and exhaust the air at the left side of the chassis (when the chassis is viewed from the front)

Airflow Through the SRX240 Services Gateway Chassis

SRX340 Services Gateway Cooling System

The cooling system for the SRX340 Services Gateway includes four fixed fans. The fans draw air through vents on the front of the chassis and exhaust the air through the back of the chassis.

Airflow Through the SRX340 Services Gateway Chassis

Hi Python,

Thanks for your response.

Actually both SRX'es weren't optimally placed, both the side-to-side cooled SRX240 and the front-to-back cooled SRX340 get their air from the warm side of the rack, hence the RE temperatures being the same (around 44-45C) (The classic problem with network-interfaces of systems always located at the back of systems, not the front)

The warm side is not that hot by the way, inlet temperature is around 25C if I had to guess.

Can you tell me anything about a healthy temperature for the RE CPU?

The fan-speed is normal, I've seen no alert, but I'm still a bit worried since the CPU temp is over 70C and way higher than that of previous models.

Hi,

not specifically a SRX340 but I have a SRX300 at home put inside a drawer together with an EX2200-C-12P-2G. CPU temperature on the SRX is just around 76-77C and has been running like this for more than 6 months without any issues.

I have a friend who has a SRX340 chassis cluster where they are positioned correctly in regards to airflow and there the CPU temperature is just around 40C - so agreed your boxes are rather hot but I wouldn't be concerned before they go above 80C on the CPU (personal experience, not official Juniper recommendation).

Hi Folks,

Please find the recommended SRX340 Services Gateway Environmental Specifications,

https://www.juniper.net/techpubs/en_US/release-independent/junos/topics/reference/specifications/services-gateway-srx340-environmental-specifications.html

The fan speed changes at the threshold when going from a low speed to a higher speed. As the threshold is not yet met for the routing-engine as a whole; the fans are at normal speed in your case. Moreover, the "Routing Engine CPU" which picks up the temperature sensor of the CPU. It is always recommended to place the box in right Environmental conditions! However, you can also track the alarms Yellow alarm/Red alarm in the box and react on the worst case to avoid any system shutdown due to High Temperature.

srx340> show chassis temperature-thresholds       

                           Fan speed      Yellow alarm      Red alarm      Fire Shutdown

                          (degrees C)      (degrees C)     (degrees C)      (degrees C)

Item                     Normal  High   Normal  Bad fan   Normal  Bad fan     Normal

Chassis default              35    45       50       40       75       65      100

Routing Engine               35    45       50       40       75       65      100

srx340> show chassis fan                                  

      Item                      Status   RPM     Measurement

      SRX340 Chassis fan 0      OK       6540    Spinning at normal speed

      SRX340 Chassis fan 1      OK       6540    Spinning at normal speed

      SRX340 Chassis fan 2      OK       6420    Spinning at normal speed

      SRX340 Chassis fan 3      OK       6360    Spinning at normal speed

srx340> show chassis routing-engine               

Routing Engine status:

    Temperature                 38 degrees C / 100 degrees F

    CPU temperature             60 degrees C / 140 degrees F

    Total memory              4096 MB Max  1311 MB used ( 32 percent)

      Control plane memory    2624 MB Max   735 MB used ( 28 percent)

      Data plane memory       1472 MB Max   559 MB used ( 38 percent)

    5 sec CPU utilization:

      User                       6 percent

      Background                 0 percent

      Kernel                     1 percent

      Interrupt                  0 percent

      Idle                      93 percent

    Model                          RE-SRX340

    Serial ID                      xxxxxxxxxxxxxx

    Start time                     2016-12-27 17:39:54 UTC

    Uptime                         9 days, 22 hours, 27 minutes, 39 seconds

    Last reboot reason             0x1:power cycle/failure

    Load averages:                 1 minute   5 minute  15 minute

                                       0.00       0.05       0.06

-Python

#Please mark my solution as accepted if it helped, Kudos are appreciated as well.

Just to give you an update.

I did change the position of the SRX340, it's front is now in the cool corridor.

And temperatures changed a lot:

====================================================================================

> show chassis environment    
Class Item                           Status     Measurement
Temp  Routing Engine                 OK         32 degrees C / 89 degrees F
      Routing Engine CPU             OK         56 degrees C / 132 degrees F

====================================================================================

Thanks for posting your results .  I just got a 320 POE running 15.1X49-D130.6  that is  used as branch office and its running temp of 66

If I close the cabinet *not rack rmounte * the temp goes up to 70C.   I have not see any issues as of yet.

Another thing i noticed.. My temperature-thresholds have different values.

show chassis environment
Class Item Status Measurement
Temp Routing Engine OK 45 degrees C / 113 degrees F
Routing Engine CPU OK 66 degrees C / 150 degrees F
Fans SRX320 Chassis fan 0 OK Spinning at normal speed
SRX320 Chassis fan 1 OK Spinning at normal speed
Power Power Supply 0 OK

show chassis temperature-thresholds
Fan speed Yellow alarm Red alarm Fire Shutdown
(degrees C) (degrees C) (degrees C) (degrees C)
Item Normal High Normal Bad fan Normal Bad fan Normal
Chassis default 45 55 60 50 70 60 90
Routing Engine 45 55 60 50 70 60 90

show chassis fan
Item Status RPM Measurement
SRX320 Chassis fan 0 OK 3720 Spinning at normal speed
SRX320 Chassis fan 1 OK 3720 Spinning at normal speed