RAID-1 mirror of a RAID-0 array?

garak

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Mar 7, 2001
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This may sound like a dumb question, so please pardon my ignorance. Say you had 2x 36gb WD Raptors striped in a RAID-0 configuration using a hardware RAID controller. Theoretically, the OS would see this as a single drive. Would it then be possible to create a software RAID-1 array to mirror your RAID-0 array onto a separate 74gb WD Raptor? I'm not suggesting this would be a good idea, but I'm curious as to whether or not it could be done.
 

garak

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Mar 7, 2001
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Interesting. But does it matter that the mirror drive would be physically different from the primary drive (2x 36gb disks mirrored to a single 74gb disk)? I remember from a few years back that all the drives in a SCSI RAID array had to be identical, but I have no idea how flexible the newer SATA RAID controllers are.
 

Gondorff

Junior Member
Jul 19, 2006
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Originally posted by: garak
Interesting. But does it matter that the mirror drive would be physically different from the primary drive (2x 36gb disks mirrored to a single 74gb disk)? I remember from a few years back that all the drives in a SCSI RAID array had to be identical, but I have no idea how flexible the newer SATA RAID controllers are.

Sorry... read the edit on my last post.

That having been said, the drives in a RAID 1 do not have to be the same, so it sounds like it might be possible. However, I say again, it sounds iffy at best to me.
 

Talcite

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Apr 18, 2006
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What controller card are you using? It shouldn't be possible, because if my memory serves me correctly, I remember RAID 1 requiring identical drives.
 

Gondorff

Junior Member
Jul 19, 2006
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Originally posted by: Talcite
What controller card are you using? It shouldn't be possible, because if my memory serves me correctly, I remember RAID 1 requiring identical drives.

I would not bet much on an integrated controller allowing different drives, but it certainly is possible. For example, see this webpage on RAID 1 : http://www.pcguide.com/ref/hdd/perf/raid/levels/single_Level1.htm

"Hard Disk Requirements: Exactly two hard disks. Any type may be used but they should ideally be identical."

Also, Wikipedia seems to imply it by saying: "Such an array can only be as big as the smallest member disk."

There would be no smallest disk if they were all identical.

Not that this is something that is worth arguing over, but just thought I'd point that out...