[Discuss] Issuing the 'sync' command more than once (and a tangent on how not to run a high-tech company)

[mbr at arlsoft.com (MBR)]

I'm not disagreeing with you on that.  When I worked at Fortune, 
standard procedure was to type:

    sync
    sync
    sync
    halt

Even though the OS guys knew that typing 'sync', waiting about 5 
seconds, then typing 'halt' was really all that was necessary, most of 
the programmers writing application level code didn't know that.

But it seemed to me that your suggestion: "You could experiment to see 
if issuing it occasionally in your script helps.  Or issue it outside 
the script, even in a chron might help," was based on amental model that 
the OS is somehow tracking how many times sync() has been called within 
some timespan, and behaving differently if it's called twice rather than 
once.

    Mark

On 6/16/2012 1:23 PM, Jack Coats wrote:
> It may have been folk-lore, but the 'standard procedure' where I
> worked, before shutting down a server on purpose, was, from root,
> issue 3 commands separately when we wanted an orderly shutdown, but it
> was 'urgent'.
>
>     sync
>     sync
>     halt
>
> I am sure there is some basis in history that had a basis in fact at
> the time.  Even if the 'fact' was based on 'observation' rather than
> reality.
>
>