TuskenTower on 15 Feb 2008 13:41:02 -0800

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Re: [PLUG] Hard drive consolidation

On Fri, Feb 15, 2008 at 10:42 AM, Matt Mossholder <matt@mossholder.com> wrote:
>  On Fri, 2008-02-15 at 10:21 -0500, TuskenTower wrote:
>  > From my Solaris daze, that I know that the S90single like scripts
>  > simple transitions to rcS.d.  There is some intelligence behind this,
>  > but I never tried figuring it out.  I verified that S90Single does in
>  > fact just transition to single user mode.  For fun, I rebooted my
>  > Linux desktop into Single User mode and networking was active.
>  > Depressed at this sorry abuse of run levels, I forgot to send this
>  > email yesterday.
>  >
>  > Amul
>  Amul,
>         Not sure why you see this as abuse... if there are no network services
>  running, I can only see this as a good thing. Often, when in single user
>  mode, I need to add patches, grab config files from other machines,
>  etc.
>         I realize this is the historic way things have been done, but as long
>  as the system not dishing out services to other systems, what is the
>  harm of configuring an IP address on the interface?
>         Isn't this part of having a system that "just works"?
It's a matter of opinion on good design for a server OS.  Networking
in single user mode means that you are not in single user mode.

I understand from the desktop perspective what you are saying.  And it
makes sense, from your point of view.  However, on a server class OS,
I expect a well defined system to limit what happens at each run
level.  The way debian is setup, I do not have a well defined limit on
each run level.

I will never pretend to know what everything is doing at what run
level.  Which means that I really need the OS to show me what is
supposed to be on or off (like you said, a system that just works).
In true single user mode I could actually do the nonsense that I was
planning because everything is off.

There is purpose in the history.  Imagine that the network driver was
causing a kernel panic.  Single user mode fails in this case.  Some
things are silly.  We could do away with the concept of run levels for
something that is far more expressive (I know nothing about Upstart).

For fun, I just checked what else is turned on in single user mode.
portmap and NFS are on in single user mode.  That NFS might be client
only, but portmap is running.

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