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Date:      Thu, 12 Nov 1998 18:29:06 -0800
From:      Mike Smith <mike@smith.net.au>
To:        Greg Lehey <grog@lemis.com>
Cc:        Mike Smith <mike@smith.net.au>, hackers@FreeBSD.ORG
Subject:   Re: [Vinum] Stupid benchmark: newfsstone 
Message-ID:  <199811130229.SAA02465@dingo.cdrom.com>
In-Reply-To: Your message of "Fri, 13 Nov 1998 12:51:34 %2B1030." <19981113125134.M781@freebie.lemis.com> 

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> >> The four-layer concepts used by Veritas and Vinum have always been
> >> difficult to understand.  I'm trying to work out how to explain them
> >> better, but taking the Microsoft-style "don't worry, little boy, I'll
> >> do it all for you" approach is IMO not the right way.
> >
> > I think it's a mistake to conceal all the workings, but it's also a
> > mistake to assume that for the "common case", you need to thrust all of
> > it into the novice's face.
> >
> > The "common case" for RAID applications seems to be:  "I have these
> > disk units, and I want to make them into a RAID volume".  So the
> > required functionality is:
> >
> >  1) Input the disks to participate in the volume.
> 
> drive a device /dev/da0h
> drive b device /dev/da1h
> drive c device /dev/da2h
> drive d device /dev/da3h
> drive e device /dev/da4h
> 
> >  2) Input the RAID model to be used.
> 
> plex org raid5 256k
> 
> > Step 2 should check the sizes of the disks selected in step 1, and make
> > it clear that you can only get striped or RAID 5 volumes if the disks
> > are all the same size.  
> 
> You haven't said how big you want it yet.

Yes I have.  I've said I want to use all of these disks.  Use them all, 
dammit.

> > If they're within 10% or so of each other, it should probably ignore
> > the excess on the larger drives.
> 
> Why?  That would be a waste.  Just say:
> 
> sd drive a length 5g
> sd drive b length 5g
> sd drive c length 5g
> sd drive d length 5g
> sd drive e length 5g

If you have two drives 4.1GB and two that are 4.3GB, and you want to 
stripe them, you have to use a base size of 4.1GB and throw away 400MB. 
Either that, or you subdivide the disks into multiple partitions 
looking for the largest common submultiple.  Yuck.

> None of this requires a GUI, of course, and IMO none of it is any
> easier with a GUI.

I never said it needed a GUI.  I said it needed a tool that eliminated 
the unnecessary calculations.  The tool should do everything required 
to translate the directive "I want a RAID x volume on these disks" into 
a vinum configuration.

-- 
\\  Sometimes you're ahead,       \\  Mike Smith
\\  sometimes you're behind.      \\  mike@smith.net.au
\\  The race is long, and in the  \\  msmith@freebsd.org
\\  end it's only with yourself.  \\  msmith@cdrom.com



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