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Re: Question about umount and sync

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But this raises the question: what good is sync if it does not properly
flush filesystem-related data too?
What's the use for sync then?


On Friday, June 29, 2012 9:47:23 PM UTC+2, Joe Beanfish wrote:
> On 06/29/2012 12:44 PM, Jan Panteltje wrote:
> 
> > Question about umount and sync
> 
> >
> 
> > In the long ago past you could type 'sync' 3 times to make sure a disk
> 
> > was umounted..
> 
> > Then later I used umount, and it returned when all data was written.
> 
> >
> 
> > But I notice on my new 16GB USB sticks that the busy light just keeps flashing
> 
> > for up to a minute after umount and sync have long returned.
> 
> > So what is a reliable way to umount these things from for exmaple a script,
> 
> > and be sure before allowing the user to unplug such an USB stick?
> 
> >
> 
> 
> 
> umount has always been and still is the way to unmount. It will call
> 
> sync then detach the filesystem from the OS in a safe way so there's
> 
> no lost data. Sync just flushes the buffers. No amount of syncing does
> 
> or ever did properly detach a filesystem from the OS. Pure luck kept
> 
> you out of trouble using that technique.
> 
> 
> 
> The ongoing activity is probably the USB bus probing etc. Don't worry
> 
> about that. Umount is definitive.

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Thread

Question about umount and sync Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2012-06-29 16:44 +0000
  Re: Question about umount and sync Joe Beanfish <joebeanfish@nospam.duh> - 2012-06-29 15:47 -0400
    Re: Question about umount and sync Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2012-06-30 06:20 +0000
    Re: Question about umount and sync Richard Kettlewell <rjk@greenend.org.uk> - 2012-06-30 13:16 +0100
      Re: Question about umount and sync Joe Beanfish <joebeanfish@nospam.duh> - 2012-07-02 10:07 -0400
    Re: Question about umount and sync ameliusje@gmail.com - 2014-08-18 12:58 -0700
      Re: Question about umount and sync Joe Beanfish <joebeanfish@nospam.duh> - 2014-08-19 13:29 +0000
        Re: Question about umount and sync Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2014-08-19 14:09 +0000
          Re: Question about umount and sync Joe Beanfish <joebeanfish@nospam.duh> - 2014-08-21 13:22 +0000
            Re: Question about umount and sync Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2014-08-21 14:15 +0000

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