RAIDfail: Don't use RAID 5 on small arrays

Big storage companies stopped recommending RAID 5 a couple of years ago. But I still see small 4-drive arrays touting RAID 5 for home and small office use.

 

Big mistake. You want to save money, but you also want to keep your data. RAID 5 isn’t worth it.

 

What’s the problem?

 

The problem is that RAID 5 only protects against a single disk failure. But SATA drives are spec’d at one Unrecoverable Read Error (URE) every ~12.5 TB.

 

Let’s do the math.

Better than RAID: the new DroboPro

RAID is a bad idea for home users since its management complexity and failure modes create more problems than it solves. But protection from 1 - or better yet 2 - drive failures is a very GOOD idea.