Mismatched RAID 1, what can I expect?

[Codesmith]

I am RMA'ing a drive from a RAID 1 array. They replacement will be of equal or greater value than the original but it very likely won't be the same model or even capacity.

I have have never setup a RAID array with mismatched drives and I am wondering what if any issues might arise.

Is this going to be a problem?

 

[Paperdoc]

I have a RAID1 array, but have never had to fix it. My recollection, though, is that the RAID controller should be able to handle this. It certainly will be much simpler if the replacement unit is LARGER than the original. In that case, the RAID controller should simply create on the replcement a new partition the same size as the old one (matches partition of the existing good half of the array) and use it to rebuild the second copy. You'll be back to a fully functional RAID1. There will be an unused (and unusable) part of the new HDD that is unallocated. But I doubt you would be able to create in that spare space another partition to be used as a "normal" logical disk.

 

[Codesmith]

I think those stressing the important of using matched drives were primarily concerned with performance issues rather than wasted capacity.

 

[mford66215]

+1 for you both.

The spare capacity on the larger replacement drive won't be available to the raid system, as both drives need to support the same size partition as mirrors.

Performance issues were all about having somebody try to raid a faster rpm drive with a slower rpm drive. The raid will be established, but you're wasting your money on one of them due to speed difference.

 

[Codesmith]

So its just a matter of the array being limited to the lowest speed and lowest capacity. Nothing really to worry about then.

 

[Dougx1317]

You've talked a bit about rpm differences, but what if the two drives are different connectors? I have one SATA hard drive and one IDE hard drive. Could I use both of those for RAID 1?

 

[Codesmith]

My motherboard supports that, but I never tried it.