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To: Terry Lambert <terry@lambert.org>
cc: henrich@crh.cl.msu.edu (Charles Henrich), freebsd-hackers@FreeBSD.ORG
Subject: Re: mount -o async on a news servre 
In-reply-to: Your message of "Sun, 12 Jan 1997 12:34:40 MST."
             <199701121934.MAA26007@phaeton.artisoft.com> 
From: David Greenman <dg@root.com>
Reply-To: dg@root.com
Date: Sun, 12 Jan 1997 12:33:53 -0800
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>The "noatime" means "noatime", not "async atime".
>
>I think changing the sync frequency for update will have no effect,
>unless theres a conflict with the free buffer high water mark.  Even
>so, if that happened, then you are trading update time for blocking
>access to buffers for some users (assuming the reclaim high water
>mark is set correctly, which I believe it is).

   The two options are complimentary. i.e., "async" will get you fast file
creates/deletes, but it doesn't stop the access time from being updated - it
just delays it until the inode buffer needs to be reclaimed. "noatime" doesn't
make creates/deletes any faster, but it does completely get rid of the inode
updates when just reading the articles. Similarly, changing the update daemon
frequency from 30 seconds to 300 seconds won't help with reducing the update
of the access time on inodes. What will happen is that the inode buffer will
need to be reclaimed long before 5 minutes runs out so you'll have to write
it out much sooner anyway. It also won't help with file creates/deletes
which happen syncronously and aren't effected by 'sync'.

-DG

David Greenman
Core-team/Principal Architect, The FreeBSD Project