RAID 0 + 1 with 3HDD 2x1TB + 1x2TB

Question

Is it possible to make RAID 0 + 1 with 3 Hard Drives

I have currently setup raid 0 with 2x~1TB HDD (1.8TB approx)

Now i got 2TB HDD (1.9TB approx) which i want to be as a mirror drive.

Is is possible to do a hardware raid 0+1 with 3 HDD

2x1TB Same HDD 1x2TB Another HDD

All have SATA Interfaces

Answer 1

You can't build a RAID 0+1 with anything less than 4 drives, since 0+1 is "Striped sets (needing at least 2 drives per 'set'), in a mirror (requiring at least two 'sets')".

A bit of info from Wikipedia:

RAID 0+1: striped sets in a mirrored set (minimum four disks; even number of disks) provides fault tolerance and improved performance but increases complexity.

Edit:

If your controller supports it, you may be able to get away with spanning/JBOD the two 1TB drives into one volume (or perhaps even striping/RAID0), and then mirror/RAID1 that volume with the 2TB drive.

As KCotreau suggested in his answer, you'll probably want to dig around in your chosen RAID controller's UI and/or documents and see what it can support.

Answer 2

I don't think there would be any controller that would allow this, but go into the RAID controller's interface to see.

Answer 3

RAID is generally done on entire disks, not partitions.

When a RAID controller downsizes a drive (2TB) to match the other drives (1TB), all remaining space is gone and not accessible as long as the drive is part of an array. In other words, you may not be able to use the 2TB as the redundancy disk for both 1TBs.

So I don't think a hardware RAID can solve what you are after, but a software solution might have a better logical volume handling.