I’m trying to spec some hardware to replace a spinning rust TrueNAS Core system with U.2 NVMe drives and running TrueNAS Scale.
I know what drives I want, I know what HBA(s) I want, but I need a little advice on backplanes and enclosures.
I’m currently looking at an ZhenLoong 8 Bay 2.5-inch NVMe U.2 Hard SSD Hot Swappable Module Cage Gen4 32Gb Backplane SFF8654 installation Space of 2 DVD-ROM from Zhenloong on Aliexpress (sorry, can’t add URLs here), but I was concerned by the “32Gb backplane” tag. As far as i’m aware, 32Gb (Gbit/s? or Gbyte/s?) isn’t a huge amount for a backplane for 8 drives is it? But then since the drives are paired so that 8 drives get presented on 4 SFF8654 interfaces, is it 32Gb per interface?
Has anyone got one of these and can do some benckmarking? I primarily want IOPS from this setup, so was considering 2 HBAs such as Broadcom 9670W but if the backplane hamstrings the install then I may need to think again.
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This. Stay away from the tri-mode adapters. In most cases, you are hindering performance. Not only that, but you are likely going to be cheaper in the end by just buying an NVME backplane.
So did you make a choice yet? I’m looking for ways to add a u.2 to my asus w680. I believe I have a slimsas port on my board but if I remember correctly its capped at 2gb but still useful. I still have a pcie 5.0 x8 slot left. So is hba to u.2 possible or no?
Unfortunately I learned the word bifurcation after buying my current motherboard.
Sorry I phrased that a two year old. I meant to say that i believe the Asus W680 slimsas port is capped at 2gb per second. I forget where I read it though. I wish the pcie 5.0 adapters weren’t absolutely ridiculous in price for the plx switch cards or even the 4.0 cards. My next motherboard will definitely have full x4x4x4x4 bifurcation. It really saves you money when everything is said and done. But great advice though…much appreciated!
I think others here have correctly warned me and you off of HBAs for U.2
I went for a Supermicro A+ system in the end which has the drives directly connected.
I’m now unsure what RAID level I should be using with U.2s. Normally with spinning rust i’d go RAID10, but will RAIDZ1 or 2 be performant enough not to give away half my capacity?
With respect to performance, it’s the HBA. NVMe was designed to provide direct access to storage; Tri-Mode ruins that by running NVMe drives through (or should I say “under”?) the SCSI bus… It works, until it doesn’t.
But Tri-Mode backplanes are an issue as well because they require U.3 drives and are incompatible with U.2. Wiring drives to a PCIe switch ot directly to PCIe lanes takes U.2 or U.3.
A single PCI gen 4/5 nvme has more raw IO than the 12G SAS bus. So setting up a new build with 100% NVME with a HBA is underutilizing whole bunch of performance. The Tri-mode stuff is more for adding some NVME performance, or using SAS nvme’s, with a pile of rust.
