Bug or Feature? -- Disappearing /dev/ nodes after mount

Ronald F. Guilmette rfg at tristatelogic.com
Fri Jun 12 10:16:17 UTC 2020

Thanks to Polytropon <freebsd at edvax.de> for the responses.

In message <20200612082224.9c1e3797.freebsd at edvax.de>, 
Polytropon <freebsd at edvax.de> wrote:

>> 0)  Am I the only one who has observed this specific behavior?
>No, it is normal and expected.

OK, good.  I find that it's always best to check if I am hallucinating.

>> 1)  Is this behavior documented somewhere that I just failed to look at?
>> If so, where?
>Interesting question - I would be interested in that, too.

As I said, after what was probably -not- an exhaustive search, I have
not seen a scrap of documentation in any man page, or elsewhere, e.g.
in the handbook, which documents the fact that certain device nodes
which may be present under subdirectories of /dev may disappear upon a
mount operation and then reappear once the corresponding filesystem is

>> 2)  Is there a consensus that the magical disappearance of /dev/gpt/ device
>> nodes during times when the corresponding partition is mounted represents
>> a feature, rather than a bug?
>As I said, it's normal...

"Normal" is in the eye of the beholder.

If I -physically- remove a piece of hardware from a given system, then
yes, in that instance I do expect relevant device nodes under /dev/ to
likewise go away.  Until today however, I was not aware that /dev nodes
might automagically disappear under other circumstances, and frankly, the
realization that they do was rather disconcerting, even if it does make
a kind of sense, when viewed in a certain way.

Now that I know the behavior is expected, I certainly shall not complain
about it.  It does in fact make a certain kind of sense, and I see the
probable rationale.

The lack of documetation on this behavior is however a clear trap for the
naive and unwary, and should be rectified.


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