I've been using 2 x 16TB in a mirrored array in a Windows media server using Storage Spaces, but I'm running out of space. So many movies and shows, so little time (and space)...

Black Friday rolls around and 22TB drives are £305. Sold!!

I was looking at the 22TB Western Digital Elements at first, but they need shucking. And messing around with the 3v pin. And they were 30% more expensive!

Let's see how the Iron Wolf Pro's stack up, I guess. At least they didn't try to palm off SMR as CMR, eh.

What's the best way of cycling out my current drives and bringing in the new ones?

Adding one new one to the existing Storage Spaces pool and letting it fill, then taking out the old drive(s) and putting the 2nd one in, and letting that fill?