From owner-freebsd-hackers  Sun Oct 18 23:30:45 1998
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To: Peter Jeremy <peter.jeremy@auss2.alcatel.com.au>
Subject: Re: softupdates and sync 
Cc: hackers@FreeBSD.ORG
In-reply-to: Your message of "Mon, 19 Oct 1998 07:05:13 +1000."
		<98Oct19.070445est.40346@border.alcanet.com.au> 
References: <98Oct19.070445est.40346@border.alcanet.com.au>  
Date: Mon, 19 Oct 1998 00:30:07 -0600
From: Warner Losh <imp@village.org>
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In message <98Oct19.070445est.40346@border.alcanet.com.au> Peter Jeremy writes:
: > Flush the dirty buffers to disk?
: sync(2) requests that all dirty buffers get flushed, it just doesn't
: wait for the flush to complete.

No, it doesn't schedule the writes even.  I get no disk traffic after
the sync happens.  The disk just sits there, but when I do an umount,
lots and lot of traffic happens.  I've waited as long as 5 minutes for
the sync to complete, but no disk traffic happens in this time, but
when I umount the disk, I get 30+seconds of solid disk activity.

Eg:
	rm -rf /fred/some-big-dir
	sync
<wait 5 minutes, not very little or no disk activity>
	umount /fred
<wait 30 seconds for the disk to stop updating>

Shouldn't sync schedule those 30 seconds of write to happen after I
hit return, but before I get my prompt back?  I don't think that it
is...

Warner

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