8TB Western Digital WD80EZAZ HDD – Some disks not showing up in BIOS, but perfectly fine in external USB case

I have a FreeNAS setup which looks as follows:

My pool is RAID-Z2, until recently using 6 pcs. Western Digital Blue 5 TB (WD50EZRZ). I’m fully aware that these are cheap desktop drives, but my FreeNAS is only up occasionally for a few hours for backup and Plex Media Server purposes. It’s not running 24/7/365, and so far I never had issues with desktop drives in my use case, not these ones, not the smaller ones before.

I’m now in the process of upgrading to 6 pcs. Western Digital 8TB WD80EZAZ (those aren’t available under that model number individually, but have been stripped from WD MyBook USB 3.0 external HDD enclosures. With what comes next, it should be noted that the HDDs are connected directly to the 6 SATA3 sockets on this ASRock E3C226D2I motherboard. So no PCIE-SAS board (like IBM 1015M, Dell H200 etc.) involved.

Now comes the interesting part, which makes me scratch my head:

I bought 7 pcs. of those drives (one for spare), and from those 5 were recognized instantly and resilvered flawlessly. 2 units however don’t show up at all, ALTHOUGH they work flawlessly on any external USB-SATA bridge. I’ve tried them on various SATA ports/cables in my installation … nothing (all ports and cables are known to be good).

Neither one of these 2 disks show up in FreeNAS / Storage / Disks (should be ada5 in the below screenshot), nor in the BIOS (SATA 5 says „Not detected“). But again: These 2 drives aren’t dead – they work flawlessly and perfectly fine when attached to a USB-SATA bridge.

Can you tell me what’s going on here!?


Solution found. Argh… Why, Western Digital?