Just to clarify, and ensure I understand correctly, this will work when your motherboard supports PCIe bifurcation?
Intel 900P 280GB U.2 drives $229
- Thread starter evilpaul
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Just to clarify, and ensure I understand correctly, you should ask a specific question.
I appreciate the recommendation. The thing has already shipped though, so it may be too late for me.
Some sellers, you can contact them before receiving, offer to cover some of shipping, and get their OK to refuse the delivery. lv note for carrier and sign it ...
I was referring to the 2 cards you have listed in your post.Just to clarify, and ensure I understand correctly, you should ask a specific question.
That part was clear. The vagueness was elsewhere.
My answer for you: "probably"
I have to admit, upgrading the old pool always makes me a little giddy:
I'm a little bit surprised how long the replace resilver takes for log drives though, since tey essentially only ever store a second worth of write data, I expected this to be quick! I guess it has to read through the entire pool just to be sure, for some reason.
I'm a little bit surprised how long the replace resilver takes for log drives though, since tey essentially only ever store a second worth of write data, I expected this to be quick! I guess it has to read through the entire pool just to be sure, for some reason.
Just got an offer of 2 at $188 each accepted from INTEL 280GB 900P U.2 SSD 9 2.5" OPTANE SSDPE21D280GAX1 PCIE 3.0x4 NVME New | eBay
The ones I got were new old stock, sealed in retail boxes, so no wear at all. When I read smart values on first startup they each had 1 powerup, 0 power on hours and 0 writes.
I can't speak to the ones others have received though.
I'm using the same motherboard without any problems running bifurcation on a AOC-SLG3-4E4T-O.
All 4 NVME drives are working.
-> It's known that only proper redriver or simple passive solutions are working. So in fact any cheap 4x m.2 to PCIE 16x card or the mentioned Supermicro one (there's a 2 port version too).
I would not use plx chip cards, they add power consumption (~10W) and some latency which is bad when using an optane ssd.
You need bios 3.4 (the latest) since in any other bios bifurcation settings are broken (even if one can set them in bios).
Then any port seems to bifurcate nicely (even the PCIE 8x slots).
Edit: the S2I cable is "nonsense" it only works on Supermicro X10 boards. It should enable communication to IPMI to monitor proper card/disk health.
I would not use retimer chip cards, they add power consumption (~13W) and some latency ...
Unless those redriver/retimer cards add real functionality (like hot-swap/plug), you are much better off with the "simple" (& cheaper) cards.
If you do choose to go with a PCIe_switch-based card, definitely opt for a configuration that over-subscribes the PCIe slot (i.e., #downstream [target] lanes > #upstream [host] lanes). For little added cost, you get the benefit of more effective use of bandwidth, plus the extra connectivity. Also, unless someone can demonstrate (competently) that there is measurable (and not insignificant) added latency, ignore their babble.
I agree with both of you, and going without a PLX chip was the original plan until I determined what I thought was the bifurcation not working on my board. (It turns out the Supermicro AOC-SLG3-2E4R needs motherboard firmware support via i2c in order to work, I thoguht they were just dumb bifrucation adapters, so when it didn't work, I assumed it was bifurcation that was broken)I would not use retimer chip cards, they add power consumption (~13W) and some latency ...
All of that said, going without a PLX chip is certainly better than using one both for power consumption and latency purposes, but I doubt the latency issue is particularly significant. The PLX specifications all suggest "less than 150ns of latency" which is not a lot.
Even with the added latency the Optane drives are MUCH better SLOG devices than the S3700 SATA SSD's I was using before them
I have ordered another dumb bifurcation splitter adapter to replace the PLX version I have, but as an interim solution, it really isn't bad.
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PCIe retimers seem to have (way) lower latency than plx chips (PCI SIG specces them at less than 64ns).
And they do make PCIE signals more reliable (which is their purpose if I did understand the source below).
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So in an enterprise solution, they fit well.
PCI SIG means they will have a bright future.
But hinestly, best is a passive "splitter" and short cables (or directly m.2 modules on a PCB) when it comes to performance/latency.
Then one shall consider maybe a retimer over a plx, if enough lanes (and bifurcation) are available.
And they do make PCIE signals more reliable (which is their purpose if I did understand the source below).
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So in an enterprise solution, they fit well.
PCI SIG means they will have a bright future.
But hinestly, best is a passive "splitter" and short cables (or directly m.2 modules on a PCB) when it comes to performance/latency.
Then one shall consider maybe a retimer over a plx, if enough lanes (and bifurcation) are available.
Look, you wasted your money on that retimer card. And, in an attempt to deny that, you wasted your time reading that PCISIG stuff--(1)you don't really understand it (2)you (and I) are NOT its intended audience. That stuff is for Super-Master Plumbers. You can not even imagine (let alone comprehend) that level of PCIe wrangling.
I won't waste any more time discussing this.
I won't waste any more time discussing this.
I agree with both of you, and going without a PLX chip was the original plan until I determined what I thought was the bifurcation not working on my board. (It turns out the Supermicro AOC-SLG3-2E4R needs motherboard firmware support via i2c in order to work, I thoguht they were just dumb bifrucation adapters, so when it didn't work, I assumed it was bifurcation that was broken)
All of that said, going without a PLX chip is certainly better than using one both for power consumption and latency purposes, but I doubt the latency issue is particularly significant. The PLX specifications all suggest "less than 150ns of latency" which is not a lot.
Even with the added latency the Optane drives are MUCH better SLOG devices than the S3700 SATA SSD's I was using before them
I have ordered another dumb bifurcation splitter adapter to replace the PLX version I have, but as an interim solution, it really isn't bad.
Alright, I ordered one of those Chinese boards. It made me a little nervous. I usually tend to avoid "designed in china" electronic products because of their well documented history of espionage, but it doesn't appear to have enough components on it to truly be a cause for concern.
I almost reported back here that it still didn't work. I spent a good deal of time troubleshooting, and I could only get one of the two drives to show using the Chinese non-PLX splitter. On a whim I tried a setting that shouldn't have worked, but it did.
It turns out, at least on the latest BIOS revision on the X9DRI-F they have reversed the slot numbers of the frist two 8x slots in the BIOS where you configure bifurcation.
The layout (from left to right) is as follows:
CPU 1 Slot 1: 8x
CPU 1 slot 2: 16x
CPU 1 Slot 3: 8x
CPU 2 Slot 4: 16x
CPU 2 Slot 5: 8x
CPU 2 Slot 6: 16x
For whatever reason in the bifurcation configuration screen, the two 8x slots on CPU 1 (Slots 1 and 3) are configured together as one 16x slot that cannot be configured as 16x (because they are two separate slots) so your options are 8x8x, 4x4x8x, 8x4x4x or 4x4x4x4x.
At first I inserted the card in Slot 1, and configured it so the BIOS tells you there are two 4x on Slot 1, but I only had the first U.2 drive show up.
I spent way too long troubleshooting without success. Before giving up, I on a whim reversed the setting, so that it said Slot 1 was 8x, and Slot 3 was 4x4x, and to my surprise, when I did this, it worked.
It looks like in this BIOS screen, and only in this BIOS screen they messed up and reversed Slot 1 and Slot 3.
Now that I've figured that out, it seems to work perfectly. Now I'll either sell the Supermicro PLX card, or keep it if I ever want to use it in a desktop that lacks bifurcation support.
It's a mixed bag.
They are more likely to work regardless of the motherboard, but on the flipside they introduce more latency and they use a surprising amount of power. The Supermicro PLX card I replaced got pretty damn hot!
If you can make a non-PLX card work, it is the better choice. If you can't, that's when you have to use PLX.