# FreeBSD auto reboot



## balaji18 (Aug 19, 2020)

Hi,

I am using FreeBSD 12.1 and there seems to be some issue due to which the system reboots automatically. There is no pattern. No information from log files. I have all.log enabled and all i see is the system restart messages starting with ---<<BOOT>>---.
My initial suspect was the power but if at all power goes down or a slight flickering, the system should be off and would start only on manual boot. So there is some other reason. If some software is causing this, I thought there would be some clue in the all.log file, but none. No messages for shutdown.

Also, i haven't faced this issue earlier with any of the previous FreeBSD releases.

--Thanks.


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## SirDice (Aug 19, 2020)

What is the system doing when this happens? Is it just idling or is there some application running?


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## balaji18 (Aug 19, 2020)

SirDice - thanks for the quick attention.

The machine is used as all in all, multipurposes - web server, multiple app servers run in the machine. The machine is also used as a mail server using sendmail. The last software update done was to use openmilter for DKIM signing.

--Thanks.


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## SirDice (Aug 19, 2020)

It could be memory related, bad memory could cause this. Most of the weird spontaneous resets I've had in the past 20 or so years where mostly due to bad or broken hardware, very rarely was the software the cause.


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## olli@ (Aug 19, 2020)

When a system freezes or reboots spontaneously, without a panic message or anything, this is almost always a sign of a hardware problem.

I would look at the power supply first. Sometimes there are tiny outages in the power that aren’t long enough for the PC to be switched off, but they still cause the reset line of the CPU to be triggered. Try to change the power supply if you have a spare one.

Besides that, RAM and the processor itself comes to mind. You might try to relax the memory timings in the BIOS setup – Most of the time the slowdown will not be noticeable, but it might make a machine more stable if the RAM is running at its limits. Worth a try anyway. If the problem persists, you can set the timings back to the initial values.


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## facedebouc (Aug 19, 2020)

I am running an AMD FX-6300 with an Asus M5A78L-M LX3 motherboard and had sometimes reboots. The CPU has a good cooling. I firstly replaced my power supply with a better quality and more powerful one without any success.
But since I disabled C6 state and Turbo core options in BIOS several month ago (year ?), I haven't seen any unintentional reboots.
This machine is perfectly stable.
I have to say that the BIOS is not updated since Meltdown vulnerability, but I am loading CPU firmware updates with the port
sysutils/devcpu-data


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## Bobi B. (Aug 19, 2020)

Have you tried to enable crash dumps? Take a look at dumpon(8) and rc.conf(5) (search for `dumpdev` and `savecore_enable`).


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## balaji18 (Aug 20, 2020)

Thanks to @SirDice,olli@,facedebouc ,Bobi B. for your responses.

The issue is resolved. It was a power problem. Recently we replaced the inverter with a new one. The installation engineer had put in eco mode rather than ups mode and confirmed that it was in ups mode. I went thru the manual and found how to put in ups mode. It was fraction of a second and i guess that's the reason before complete shutdown, power was back and the boot started.

--Thanks.


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