Ext3 Stride/Stripe-Width Calculation for 3-Disk Software RAID1E

For reasons too complex to get into here, I'm using a 3-disk RAID1E on some linux systems. See here for more info on that.

So my understanding is that for optimizing filesystem layout on this volume, you use the following calculation:

chunk-size = 64kB
block-size = 4kB
stride = chunk / block = 16
stripe-width = stride * ( (numdisks)/2 ) = 16 * 1.5 = 24

However, mkfs.ext3 gives a warning when I use that calculation for setting the stripe-width, that it should be a power of two.

So my question is, am I doing it right? Should I be treating it like a standard four-disk RAID10, since the stripes are of the same size?

Update: it's not a degraded array, it's a fully supported configuration. Read the link from the first paragraph.

Setting your stripe width higher than 64kB will be suboptimal.

Any write of a size higher than 64kB will result in 4 writes - one write to one disk, one write to another, and two writes to one.

Just set your stripe width to 64kB.