&gt;  People don&#x27;t tend to use parity RAID primarily for uptime&#x2F;multiple drive failures, they do it because it&#x27;s cheaper - HDD costs for a mirror&#x2F;striped-mirror implementation are always 1&#x2F;N, whereas with a RAID-6 it&#x27;s 1-(2&#x2F;N), or 1-(1&#x2F;N) for RAID-5.<p>A few years ago I built a home NAS. Back then, maximum drive sizes were 3TB for 3.5&quot;, and 1TB for 2.5&quot;. The tiny ITX case I had had one 3.5&quot; slot, and one 5.25&quot; slot.<p>So, I could either do a RAID1 with 2x3TB 3.5&quot; disks; or get a 6x2.5&quot; adapter for the 5.25&quot; bay and do a RAID5&#x2F;6 with 7x1TB for a net capacity of 5&#x2F;6 TB.<p>I&#x27;m still not sure whether it was a good idea – the hardware looks a bit adventurous: <a href="http:&#x2F;&#x2F;dl.creshal.de&#x2F;IMG_0873.JPG" rel="nofollow">http:&#x2F;&#x2F;dl.creshal.de&#x2F;IMG_0873.JPG</a>  and was loud as hell –, but it worked well for about five years without any drive failures.<p>(Then I replaced it with a smaller NAS with 2x2TB drives in RAID, because as it turned out, my interests went from binge-watching storage intensive TV series to reading more books, and I never ended up using more than 1TB storage anyway.)