One physical machine had shutdown unexpected, there is no any error log about that, only get a large ^@ in one line of /var/log/syslog file such as:

Dec  9 21:50:02 hostname CRON[74324]: (root) MAIL (mailed 716 bytes of output but got status 0x004b from MAT#012)
^@^@^@...large of ^@^@^@Dec 10 09:51:49 hostname systemd[1]: Starting Flush Journal to Persistent Storage...
Dec 10 09:51:49 hostname kernel: [...

Machine shutdowned at Dec 9 21:50 unexpected, and start by manual at Dec 10 09:51:49.

How could I find the root cause of it shutdown unexpected?

Where did it Flush Journal to?

What's the meaning of ^@ in syslog, and how could I read it?


1 Answer 1


Those are NUL bytes (i.e. bytes with a numerical value of zero), those should not exist in text files.

The crash caused the file to be extended without the data being written.

  • How could I find the couse of crash?
    – VictorLee
    Dec 12, 2022 at 2:08
  • As the question about what ^@ means is answered in several other similar questions, anwers to this question should probably focus on the other parts of the question.
    – Kusalananda
    Dec 12, 2022 at 8:58

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .