Re: RAID arrays with different size disk units?

I'll second that.

The purpose of RAID is to create swappable images of drives. If one fails, you
can pull it (hot swap) and have it recreated.  So each drives reserves space for
the complimentary drive for reconstruction purposes and they must be of same
capacity.

Technically there is no reason that a 4 GB drive could not support two 2 GB
drives, but logistically it may more work than it's worth.  In this case you
would have the two 2 GB drive support the one 4 GB drive and how would they
determine which drive gets which half?

Keep it simple.

James W. Kilgore
email@James-W-Kilgore.com



Neil Palmer wrote:

> They need to be the same capacity drives.
>
> Neil Palmer         DPS Data Processing Services Canada Ltd.
>                                              AS/400~~~~~
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>
> -----Original Message-----
> From:   Sclind2@aol.com [SMTP:Sclind2@aol.com]
> Sent:   Wednesday, December 16, 1998 6:15 PM
> To:     MIDRANGE-L@midrange.com
> Subject:        RAID arrays with different size disk units?
>
> Are there any circumstances where disk units of a different size can be added
> to an existing RAID array?  The Backup and Recovery manual states that you
> need 4 disk units of the same size to start RAID protection, and that
> additional units can be added later.  But it is unclear whether these need to
> be the same size units.
>
> I currently have one RAID array that isn't full; it has four 2gb drives (raw
> size).  Can I add 4gb (or larger) disk units into this array?  We have added
> disk units into an existing array in the past, but they have always been of
> the same size.
>
> If this can be done, what is the resulting usable size of the new units?  In
> the above case, establishing RAID protection ended up leaving us with four
> units of 1475mb each.  (I.E., 25% was used on each of the four units).
>
> Scott Lindstrom
> Zenith Electronics Corp
>
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