Mysterious restart after apparent shutdown at 18:02

Receiving an email stating:

> Host initiated restart - Completed Fri, 23 Feb 2018 18:59:23 GMT

I checked /var/syslog and found:

Feb 23 18:02:16 limynode postfix/smtpd[27991]: disconnect from unknown[91.200.12.225]
^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@Feb 23 18:59:29 limynode rsyslogd: [origin software="rsyslogd" swVersion="8.4.2" x-pid="3450" x-info="http://www.rsyslog.com"] start
Feb 23 18:59:29 limynode kernel: Linux version 4.14.17-x86_64-linode99 ([email protected]) (gcc version 4.9.2 (Debian 4.9.2-10)) #1 SMP Tue Feb 6 19:09:58 UTC 2018
Feb 23 18:59:29 limynode kernel: Command line: root=/dev/sda console=tty1 console=ttyS0 ro  devtmpfs.mount=1
Feb 23 18:59:29 limynode kernel: x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'
Feb 23 18:59:29 limynode kernel: x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers'
Feb 23 18:59:29 limynode kernel: x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers'
Feb 23 18:59:29 limynode kernel: x86/fpu: xstate_offset[2]:  576, xstate_sizes[2]:  256
Feb 23 18:59:29 limynode kernel: x86/fpu: Enabled xstate features 0x7, context size is 832 bytes, using 'standard' format.
Feb 23 18:59:29 limynode kernel: e820: BIOS-provided physical RAM map:

Is this related to:

https://status.linode.com/incidents/2088k0rt4rb9

?

Was the system offline for nearly an hour? Any idea what is the garbage in syslog?

4 Replies

If you're in Fremont, yes, that's why it happened.

(Or there was a huge coincidence at the exact same time.)

Your Linode's host lost power, so your Linode shut down… um, suddenly.

^@ is a representation of a zero (null) byte. The syslog file became slightly damaged due to the system being improperly shut down.

During the seconds before the Linode crashed, data were written to the syslog file. Power was lost after the file was extended to make room for it, but before the data were actually written to the disks, so the actual data were lost and replaced with zeros.

Yes, assuming the clock was reasonably accurate, it probably was offline for close to an hour. It took some time to fix the problem, some time to turn the host back on, and some time for the host to boot your Linode.

There is a mention in Linode Status https://status.linode.com/

"Power failure" - that happened a few years ago at Fremont…

Quite scary!

Hope we're not going towards the same problems.

Almost all of the previous Fremont problems were in a different building.

Feature request: when possible, send follow-up notifications with a link to system status posts describing the issue.

Cheers,

-dre

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