The next evolution to my home server, named “koh” from the Avatar the Last Airbender universe, continues. This time it mostly involves changing cases, adding 2 more 3.5″ drives, and PCIe bifurcation to allow for both a LSI HBA to manage all 8 drives plus an NVIDIA T400 4GB GPU to do Plex transcoding and codeproject.ai object detection for the security cameras. The hardware is mostly the same as shown in the Node 304 Mini Cube (2023) section posted before.
The case is a “Sagittarius” 8-bay case, which is made by several Chinese manufacturers and sold online from different retailers. It is a micro-ATX case with 8 hot-swap drive bays on a SATA/SAS backplane.
There are 2 vertical halves to this case – the left which has 2x 120mm intake fans, the motherboard and the power supply, and the right which has the 8x hot-swap drive bacys, and in the back 2 more 120mm exhaust fans. The drives are accessed by pulling off the magnetically held front plate via that strap. The separate compartments do a good job pulling air through the case and keeping things cool. There is a power button, USB type A and C on the bottom left.
The side panels are uninteresting. The motherboard/PSU side has perforations for more cooling, while the hard drive side is a solid metal plate to pull all cooling through the drives at the front.
The back shows the 2 vertical compartments again. The fans on the left cool the hard drives. The right side has the motherboard I/O panel in the middle, to the right the power supply, and below it the expansion slots. From top to bottom, there is an LSI 9211-8i HBA to handle the 8x hard drives, then a USB expansion breakout, and below that the NVIDIA T400 4GB card.
The motherboard/PSU side is a bit cramped, but it will fit a micro-ATX motherboard. The clearance between the top of the CPU cooler and the full-size PSU is tight, so a low profile cooler will be a must. My motherboard has a built-in low profile cooler and just fits.
The mini-ITX motherboard only has 1x PCIe x16 slow, but you may notice there are 2 PCIe devices. Here’s what I did…
I bought a C-Payne PCIe Bifurcation Card, x16 to x8, M.2 (x4), M.2 (x4) which will allow a half-height card to plug in on top and be the proper height for a full-height card. I felt this connection would be the most reliable, so I put the LSI HBA into this slot. In one of the M.2 slots, I put this x4 M.2 -> PCIe slot adapter and plugged into it the NVIDIA T400. I didn’t end up using this specific adapter in the left picture, opting for one with a right-angle plug like in the right picture.
One interesting side-effect of this setup, after telling the motherboard to bifurcate the x16 slot into 4 x4 slots, is that the bandwidth is limited to the 2 devices, but not enough to make a real-world difference. The LSI HBA would normally run at PCIe gen2 x8 speeds, but here runs at gen2 x4. The GPU would normally run at PCIe gen3 x16 but is running at gen3 x4. The 8 hard drives would never push enough data over SATA to saturate the gen2 x4 link, nor Plex or codeproject.ai enough to saturate a gen3 x4.
The GPU gets an additional power connector, to make sure both devices together don’t pull more wattage from the motherboard than allowed. So far this setup has been very stable and I’ve had no issues since setup.
Here is another view of the PCIe setup:
The hard drives were expanded from the maximum of 6x 8TB of the previous case, the 8x 8TB drives in this one. Going from 6 to 8 drives for the ZFS raidz2 pool has made for more available space and a relative sweet spot in redundancy and capacity. I’ve considered replacing the mini-ITX motherboard (with a soldered CPU and integrated cooler) with a new micro-ATX board and more modern CPU and memory, but the AI bubble makes buying new DDR5 memory, especially 128GB+ of it, not very attractive. This hardware fully meets my needs for now, and I am enjoying my self-hosted services and ability to tinker still.