I've had some issues recently that I'm wondering if this card isn't handling 4TB & 5TB drives very well.  When the system is doing something that's high load, such as a data rebuild, parity rebuild, and sometimes (rarely) parity checks, I'll suddenly have 5 or so drives disappear. All of the drives that drop out are attached to the same card. It's not always the same card that this happens to either.

 

Could it be power related? I'm using an Antec Truepower 650, 2x5TB, 4x4TB, 8x3TB, 4x2TB, 2x120GB SSD.  Everything else in my build is the 20 drive beast build.

 

 

The common denominator in your troubles is that all drives are active at once during those operations.

 

... this definitely makes me suspect it's a power issue.    I'd replace the power supply with a high-quality 80+ certified unit of at least 750w with a single 12v bus.

 

Now that you've reinforced that possibility, I looked and I've just added a 5TB drive that consumes 11.3 watts at load, so that's making a lot of sense now.

 

I ordered a EVGA SuperNOVA 850  220-G2-0850-XR, so I'll install it and see how things handle after that.

I looked up the specs of your Antec power supply and it appears to be a multi-rail.

 

I don't think the SASLP should have trouble with 4TB and 5TB drives. I have 8TB and 4TB drives hooked to mine with no stability problems. If it was a problem, we would hear about it because so many use this card.