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Date:      	Wed, 29 May 1996 14:48:46 -0800
From:      Sean Doran <smd@cesium.clock.org>
To:        davidg@Root.COM, terry@lambert.org
Cc:        hackers@freebsd.org, jgreco@solaria.sol.net, rashid@rk.ios.com
Subject:   Re: Breaking ffs - speed enhancement?
Message-ID:  <96May29.144850pdt.119171-19642%2B41@cesium.clock.org>

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So what's wrong with turning off the update daemon on such machines,
or at least making it call sync(2) at much less frequent intervals?

This is a venerable practice on far-too-busy news machines.

Also, another venerable practice is to make the inode cache
*huge* (tens of thousands of inodes in ninode/desiredvnodes,
as appropriate).

I would be willing to bet that these two changes, neither
of which needs anything more than adb/gdb, and both of which
are widely portable to 4BSD systems of all types, will make your
max-ed out disks much happier.

Now what I'd really like to see being worked on for flinging
around news too fast is playing with 4.4BSD union mounts so that 
at the lowest layer one finds the oldest articles, and in
each higher layer, one finds newer articles, and the upper
layer is current.

Expiry would then mean:

-- stop incoming news
-- unmount lowest layer 
-- newfs lowest layer
-- mount former lowest layer as upper layer
-- restart incoming news

and then some bookkeeping as needed to adjust the history
and overview files, which probably can be done in spare
cycles.  

Unlink(2) is too bloody slow.

You probably lose if you are doing mostly-reads on articles
several generations old.  If, however, you're a big news distribution
site...

	Sean.



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