After upgrading to 6.12.3 today I found that the same two drives had died again. A physical inspection last time didn't turn up anything, but I decided to check again. I noticed that the drives that had "died" were connected to my HBA with one of those SAS to SATA cables, and the cable on the SATA end had gotten a bit bent as I built the NAS in a mini-ITX case.
I replaced the entire cable and it seems like the problem has been fixed? I'll keep the old cable around, but as long as two drives don't drop out during upgrades I think it's safe to rule this as a cable issue. The missing drives didn't even show up in the SAS configuration utility when the suspected faulty cable was used.
moral of the story: change cables and don't build your NAS in a mini-ITX case
EDIT: after further inspection it seems more like a cabling issue, not a driver issue. I found the following in the kernel log:
`dmesg | grep r8169` (r8169 is the driver used by Realtek RTL8111):
[ 41.922626] Generic FE-GE Realtek PHY r8169-0-500:00: Downshift occurred from negotiated speed 1Gbps to actual speed 100Mbps, check cabling!
[ 41.922658] r8169 0000:05:00.0 eth0: Link is Up - 100Mbps/Full (downshifted) - flow control rx/tx
Hope someone else finds this useful. As far as I can tell, the r8169 driver and RTL8111 works fine on UnRAID – if you also can't get gigabit check your kernel log and cables!
