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Author Topic: ERS 4850 stack rebooting frequently  (Read 3112 times)

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Offline Suraj

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ERS 4850 stack rebooting frequently
« on: May 15, 2015, 10:03:53 PM »
Hi Guys,

We have a ERS 4850GTS-PWR+ stack of 6 units, which is frequently rebooting itself for unknown reasons. It rebooted 4 times in the past 36 hours without any intervention.

Initially customer rebooted it after seeing Amber light on Stack cable between unit 1 and unit 2. After rebooting, the light turned green (according to customer).

Currently unit 1 is base and from the logs i can see that all the units have been rebooted at the same time, which suggests a problem with power,

Please find the output of show stack-info uptime

Unit# Switch Model     Unit UpTime
----- ---------------- --------------------
1     4850GTS-PWR+     0 days, 06:37:17
2     4850GTS-PWR+     0 days, 06:36:54
3     4850GTS-PWR+     0 days, 06:36:34
4     4850GTS-PWR+     0 days, 06:36:09
5     4850GTS-PWR+     0 days, 06:35:48
6     4850GTS-PWR+     0 days, 06:35:30

Also find the output of show stack health

UNIT#            Switch Model       Cascade Up            Cascade Down
1 (Base)          4850GTS-PWR+      OK                    OK
2                 4850GTS-PWR+      OK                    OK
3                 4850GTS-PWR+      OK                    OK
4                 4850GTS-PWR+      OK                    OK
5                 4850GTS-PWR+      OK                    OK
6                 4850GTS-PWR+      OK                    OK

Switch Units Found = 6
Stack Health Check = OK - RESILIENT
Stack Diagnosis = Stack in full resilient mode.

The local tech also confirmed us that there is no problem with stack cable or power cables after he checked it physically.

No exceptions recorded in the logs and also in system last-exception.

I am in a dilemma to replace that cable between unit 1 and 2.

Also Stack forced-mode and stack-monitor is disabled.

Can you guys suggest how to troubleshoot ?


Offline MatzeKS

  • Sr. Member
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  • Posts: 311
    • matzeks
    • Controlware GmbH - Germany
Re: ERS 4850 stack rebooting frequently
« Reply #1 on: May 18, 2015, 04:53:34 AM »
Hi, please check output of:

# CLI:
sho system last-exception unit all

sho boot

ACE-Fx #00050

Offline Johan Witters

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  • Posts: 252
    • BKM Networks
Re: ERS 4850 stack rebooting frequently
« Reply #2 on: May 19, 2015, 04:57:36 AM »
You can run the stack loopback internal and external tests, but you'll have to take the stack offline to do the tests..

the output of show system verbose gives you the reason of the last reboot.. if this mentions "power cycle" you could have issues with the power grid, or problems with the power supply of the switch(es). I had a 3500 a few weeks ago with a faulty power supply rebooting a lot, sometimes a few times in a week, but also multiple times per hour..

Kind regards,

Johan Witters

Network Engineer

Offline parthiv_s

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  • Posts: 1
Re: ERS 4850 stack rebooting frequently
« Reply #3 on: June 02, 2015, 03:14:51 AM »

Can you please check the logging file detail and cpu utilization ?

show fulltech khi
show logging file