Looking for an actual experience of RAID 5 2 drive failure? [closed]

I'm wondering if anyone has any personal experience of RAID 5 2 drive failure with large drives?

As I understand it, the theory is that with large 1-2TB drives, if one drive fails in the raid set, it needs to rebuild everything so is thus hitting all the other drives very hard, and the chance of another failure goes up, especially if the drives were from the same manufacturing batch. And if you lose another drive, you lose all the data.

This is usually explained after the statement "RAID is not backup" which I agree with.

The theory of this makes sense, and I understand it, but does it really happen?

Solution 1:

Yes, I've had it happen to me. A set of 4 (consumer grade) WD 500 drives went bad over the course of about a week. I was slow to replace the first, and didn't take the array offline, and lost all my data when the second failed. I re-used the remaining two good ones, and one of them failed within the next month. They were all properly cooled and cared for. I can only say that I now believe the "bad batch" rhetoric.

In a separate incident, I had 3 separate drives of different makes and models fail within a month of each other, though I'm pretty certain that the reason they failed was due to improper ventilation. Don't cook your drives!

Solution 2:

This has actually happened to me, though, it wasn't really the most common way a drive would fail. I had 4 500gb external sata drives in raid 5. They were attached to a cheap old IBM rack mounted server. The whole setup was tucked away under the stairs and one day, either a rat or a bunny, but something chewed through some power cables and 2 drives were shorted out. All the drives were in cheap external enclosures so I guess i shouldn't have been so surprised.