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Date:      Wed, 15 Mar 1995 10:42:19 -0800 (PST)
From:      "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com>
To:        phk@ref.tfs.com (Poul-Henning Kamp)
Cc:        current@FreeBSD.org
Subject:   Re: newfs: sectors per cylinder (4096) disagrees with disk label (36)
Message-ID:  <199503151842.KAA13193@gndrsh.aac.dev.com>
In-Reply-To: <199502210226.SAA21140@ref.tfs.com> from "Poul-Henning Kamp" at Feb 20, 95 06:26:18 pm

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> 
> > > > This is caused by phk's changes to the behavior of newfs, it now 
> > > > uses 1 head/cylinder, 4096 sectors/track by default.  This was an
> > > > attempt to increase performace.  I have found that it does nothing
> > > > for any disks I use and just leads to problems while newfsing several
> > > > of them.
> > > How did you measure this ?
> > 
> > Iozone using auto and 128 8192 and dd to/from /dev/{null,zero}.
> > Note that the newfs code already defeats the rotational delay stuff
> > by -n 1 -d 0 defaults.
> > 
> Try this:
> 
> 	newfs /dev/rsdXy
> 	mount /dev/sdXy /mnt
> 	(cd /usr/src ; find . -print | cpio -dumpV /mnt)
> 	time tar cf /dev/null /mnt
> 	umount /mnt

I have run several iterations of this using the default newfs and
using the -t 0 -u 0 overrides and can find no significant difference
now that the ufs code has been fixed to deal with NRPOS=1.

If no one objects (more specifically if Poul-Henning does not object) I
am going to removed the newfs hacks for 1 track of 4096 cylinders.  And
fix src/etc/Makefile to not have the -t 0 -u 0.


-- 
Rod Grimes                                      rgrimes@gndrsh.aac.dev.com
Accurate Automation Company                   Custom computers for FreeBSD



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