[aclug-L] Re: RAID question?

["Jonathan Hall" <flimzy@xxxxxxxxxx>]

An adendum...

It may be possible to use mismatched drives on a RAID controller to the
extent that they have the same number of cylinders, sectors, and heads.

For instance, if you have two drives... on with 6 heads, 55 sectors, 1010
cyl, and another with 989 cyl, 15 heads, and 56 sectors...

You might be able to use each as a 6 head, 55 sector, 989 cylders drive.  In
some cases (such as my example), you'll end up losing lots of HD space.  The
first drive I mentioned is a 170mb drive, the 2nd a 420mb drive (two drives
I hapened to have lying on the floor).  The 2nd was a 420mb.  By using the
lowest of each value, I'd be able to use only 167mb from each drive... or a
total of a 334mb RAID array.  Not a very good use of a 420mb drive IMO :)

For some RAID controllers (I would guess only the more expensive ones) it
may be possible to partition off just the first part of the larger drive to
equal the partition size of the smaller drive, and use that.  In my example,
create a 170mb partition on the 420mb drive, and disregard the rest.  This
would allow for a 340mb RAID partition--a bit better than the cyl/sect/hd
scanario above.  It would also result in lesser performance... and still
isn't a good use of a 420mb drive.

It might be useful if that's possible in a situatio where both drives are
nearly the same size (such as your 40g and 39g drives).

Whether that works will be a question to ask your RAID controller manual :)






----- Original Message -----
From: "David Carmichael" <dec29111@xxxxxxxxxxxxxxxx-spam>
To: <discussion@xxxxxxxxx>
Sent: Thursday, October 03, 2002 11:32 AM
Subject: [aclug-L] RAID question?


>
> Question about RAID ARRAY
> [ RAID 0 / Level 0 is also referred to as "striping".]
>
> While in a perfect world both harddrives would be the same size, make and
> model...
>
> _But_
>             MUST both drives in a RAID ARRAY be the same size, make and
> model??
>
> I have two WD drives one 40gb and one 39gb.
> I have an IDE RAID controller which I am currently only using as an add on
> IDE controller.
>
> --David
>
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>

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