Your opinion is noted, and I’ll be sure to give it the weight it deserves.
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“Unraid” and “stability” do not go together without glue in the form of the negation prefix “in”. As for TrueNAS, Citation Needed.
Actually, they do, by virtue of their market position as feedstock for Super China Happy Sun products. There is literally no other use for them.
It’s not a TrueNAS problem in any way, nor is it a driver problem. Or an OS problem more broadly. It is 100% a problem of crap hardware that is explicitly not supported by Intel (and if you dig it up, I bet AMD’s chipsets don’t either). That leaves the likes of Marvell and ASMedia, who struggle to make a simple AHCI controller on a good day, never mind the port multiplier nonsense.
Why do I say it will not change? Because there is zero market for it. There never was. Serious storage has been served by SAS for decades, competently and relatively affordably. Consumers never gave a damn, much less in 2024 when SATA is borderline retro on most machines. Nobody in their right mind is going to spend a cent solving this problem, when they could spend it on literally anything else.
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What’s the ASMedia controller used in some MiniXLs from IX?
If you can get that chip on a card, it’s probably the only officially supported one.
Port multipliers are bad for ZFS because they halt the other drives from talking when one of the drives is hanging. Thus you get multi-drive faults, when you get a single fault. This only shows up when things go bad.
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IIRC, those were Marvell. And one of them needed a special firmware update that was unobtainium other than through iX. And it still caused trouble occasionally.
ntel AX210
“Unraid” and “stability” do not go together without glue in the form of the negation prefix “in”. As for TrueNAS, Citation Needed .
LOL. Give me a break! People have been using unRaid reliably for a long time . But sure, make uneducated assumptions if that makes you feel better.
Actually, they do, by virtue of their market position as feedstock for Super China Happy Sun products. There is literally no other use for them.
SATA port multipliers go back over two decades and allowed many more hard drives to be connected to a sata controller when putting that many sata controllers in a server just wasn’t possible. It was created for a use case and still exists today because there is still a use case for some. The technology isn’t inherintly wrong because you say it is. If implemented properly it shouldn’t cause instability on decent controllers that are designed to properly handle it. Just the fact that it is poorly implemented in many cheap products from china doesn’t make it ineherintly bad.
Perhaps one day better port multiplie support will exist in Truenas.
Fact check bro. Intel’s ACHI specifications do support port multiplication. That doesn’t mean it’s implemented in all their products. Possibly not in any current ones, but it does remain in the specification. What people spend time and money at the end of the day doesn’t rely on your opinion. You are welcome to your opnion, but at least actually stick to facts if you are going to present things as fact.
I didn’t expect the first entry on my ignore list here would happen so soon. Ah well.
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Name a single serious server that uses a SATA port multiplier. I will not hold my breath.
Try “not implemented in any products”. As a representative sample, here’s a quote from the Lynx Point/8-series PCH datasheet:
Port Multiplier Port (PMP)—R/W. This field is not used by AHCI
Why is that relevant? That’s the only mention of Port Multipliers outside of some remnants in the GPIO portions of the datasheet. That’s Intel stating “we don’t support Port Multipliers as defined in the AHCI specification in this present AHCI implementation”.
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On a moderation note, I will treat any further statements of fact on port multipliers which are not accompanied by relevant citations as being made in bad faith.
For those with an ASM1166 based controller, may want to delay upgrading to Dragonfish
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Not entirely clear to me if it’s a controller issue or if there’s a port multiplier in the mix. I think some folks are starting to see port multipliers where there only crappy AHCI controllers, which makes things hard to follow…
I am the author of the post @Stux referenced above (although now I’ve seen others reporting the same issue), and in my case the product is the “MZHOU PCIe SATA Card 8-port” (link) which I’ve come to understand (mainly from this blog post) is based on the ASM1166 SATA controller, which is a cheap SATA controller with less bandwidth than some but no port multiplier, combined with a port multiplier to get the extra ports.
So I’m not sure that the issue would occur with an ASM1166 card without the port multiplier. There are now multiple bugs filed by different people (NAS-128478 being the main one, the others are duplicates of it) so hopefully that will help disambiguate the specific hardware affected.
FWIW, though, in this and the other thread, as a “casual” user of TrueNas (shared storage and backups for my kids, etc) I found the snarky comments around port multipliers rather helpful. I’ve always thought that if they work, they work, and they just might be slower and less reliable than enterprise gear. I’m not gonna ever have ECC RAM or enterprise SSDs in my home TrueNAS server, because it is always going to based on my kids’ last gaming PC that finally got too old to work for games. (Currently, I’m rocking ASRock Z390 with a 9th-gen Intel CPU.) So I didn’t think I needed an HBA either.
But the “well, duh, you’re using a port multiplier, bro” comments did spur me to dig into the docs/blogs a little more and — TL;DR — after reading various info and experiences, I did, in fact, order a used LSI HBA. (Or what purports to be one anyway — I live in Japan, and the eBay ones plus shipping are quite expensive for us here, especially with the collapse of the JPY, so what I ordered might be a fake — we’ll see.)
EDIT: Also, if the problem does happen to your machine, it is immediately obvious and you can simply downgrade using the web UI to 23.10 and all the data is fine and usable again. So, not a big risk in updating.
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@axhxrx thankyou for the candid reply
I’m not trying to disparage people’s hardware, but rather work out what works and what doesn’t. Unfortunately there are very good reasons why Port Multipliers are a bad idea, what I’m not so convinced about is that all SATA controllers are inherrently flawed.
At least by having this thread, we can try and get some up-to-date experiences from people now that TrueNAS is based on Linux, rather than BSD, which does make a difference to its hardware support.
Hopefully we can get to the bottom of it… Personally, if I needed a couple of extra SATA ports in my build I would probably use a SATA M.2 card… but it seems that Port Multipliers are simply a no-go, especially at the moment with Dragonfish
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Sure. To be clear, I didn’t find your comments snarky at all, I was more referring to the memes like this. (But even those kinds of things are actually pretty helpful to help figure out Hmm should I allocate time to understanding this better?)
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The point is that none is playing around but truly using those adapters: one thing is saying “everyone, here Is this new thing I will test and come back to you” another is “Hey, why things don’t work? I’m using this cheap thing btw”.
We welcome everyone willing to test and give us feedback, even when it has been proved multiple times it does not; we do not welcome people making baseless claims.
If you see things that way you have an issue with how you view things. Speaking from experience and knowledge and suggesting using proper, reliable hardware its one of the strenght of this community; are you expecting a tech forum to not help and not educate?
You do not build a NAS with a mini pc here.
Either you have not looked into the old forum or you don’t know how to search.
I would argue that choosing unsuitable hardware is bad planning.
Everything has already been answered by eric, and I will just say that your attitude is totally wrong if you care about this community (which you clearly do not) and want to make a change.
That’s a frequent dabbler’s honest reaction when seeing someone it’s using port multipliers, I would not see that as snarky.
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JGreco’s resource about port multipliers does state that some, but not all, Marvell or ASMedia SATA controllers are acceptable. If you’re absolutely desperate to add a couple of SATA ports in the smallest possible footprint, you may want to dig further with that but it’s going to be more validation trouble than a $50 M.2 card is really worth. That energy would have been better spent trying to find a small footprint motherboard with enough native SATA ports.
All occurences of port multipliers are bad. Period.
Chipset ports are good.
LSI 2008/2308/3008 and their OEM versions from Dell/HP/IBM/Lenovo are the way to go to add more ports.
These are simple and safe rules. HBAs can be found second-hand for less than what a “good” (or “acceptable”) SATA-ports-on-M.2-stick costs new.
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This is true. I read the specs. It’s incompatible with ZFS’ idea of a reliable and queuable block device.
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Allow me to jump in here.
We can certainly encourage/discourage certain component choices, but ultimately each user is responsible for their own decisions, their own level of acceptable risk tolerance, and their desired system form factor/budget.
It’s important to note that M.2 is only a form factor decision - bite-sized PCIe is still PCIe - but the crux of the problem rests on three major issues:
- The chipset used to provide SATA connectivity (including driver support)
- Manufacturing quality of the device itself
- Presence or absence of a port multiplier
While SCALE has expanded the playing field relative to CORE (where “Just Buy LSI” was the rhyme of reason) - there are still definitely “tiers” of driver support and functionality within the Linux kernel, and the vast majority of M.2 SATA controllers use a “lower tier” chipset. Intel and AMD are preferred over all others, Marvell and ASMedia share the next space, and JMicron brings up the rear (but has made improvements recently.)
A poorly manufactured or improperly cooled device can of course contribute to instability - whether the chip responds by temporarily throttling commands or running to thermal failure though is another question. M.2 slots traditionally do not get the same quantity of airflow as traditional PCIe, and this is exacerbated by the “cable spaghetti” that comes from these cards. Prefer cards with heatsinks, if possible.
Finally, port multipliers - the thorniest piece of this argument. Quite simply, they are to be avoided for multiple reasons.
The first is the bandwidth argument - the most common multipliers are 1:5 - so one SATA port worth of bandwidth being spanned across five downstream devices. That means your 600MB/s of theoretical SATA3 bandwidth is cut into 120MB/s per device - a definite limitation for SATA SSDs, but it can also be a limiter on sequential I/O to spinning disks. With sequential resilver and scrubbing, this is a very real thing to hit.
The second is the nature of the port multiplier itself - if it’s using “Command-Based Switching” then you can basically have only a single command queued against any of the devices behind the port multiplier, and all others are blocked. This means that your performance tanks even more than the bandwidth cap, because it’s like having a common media akin to a “hub” vs a “switch” in the old networking sense. If it’s using FIS-based (hardware) switching, then it’s able to queue up against multiple devices, but it’s still sharing the bandwidth.
And finally, if a single device behind a SATA port multiplier hangs up or fails to respond to a command, it could (“will” in the command-based switching model) cause all devices behind the PM to be non-responsive. Not exactly a good thing as RAIDZ6 doesn’t yet exist. 
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This is absolutely the key.
I have a few machines that are 1 liter or smaller and have some data they share with other machines on the network. I would never consider calling them a “NAS”. Maybe someday when the bugs on the multi-M.2 micro motherboards are worked out, we can have a real NAS in a tiny form factor.
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Linking to a similar thread on old forum for posterity
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I think something many of the moderators here ignore is that there are plenty of people who use Truenas in unsupported unreccomended configurations at home who also use it in a professional enterprise setting. I was an Isilon Integrator before eventually using Truenas in many projects. My issue isn’t that people have differing opinions.
My issue is with the often condecending attitude by some. This insessant whining not to do something a particular way in someone’s home lab experiment. Sometimes the responses by moderators are plain rude, if not helpful at all. I mean I was threatend action by @ericloewe, for merely stating my opinions supported by facts, for not citing my sources. Despite those facts being pretty easy to find with a simple google search, I didn’t see anyone else citing anything. I was then promptly suspended from this forum, for which I appealed and got reinstated pretty quickly. Granted he blacklisted my IP too so now I have to login with a VPN. I’m not holding my breath that I won’t be prompty suspended again just for posting this reply, but I feel that it needs to be said.
At this point I am not going to respond to every single point in your reply because honstly it seems it will just be a neverending back and forth. I will respond to one point though…
You do not build a NAS with a mini pc here.
LOL. “You don’t”. I do and I will. I have every intention of doing so for my own home built DIY solution for non critical data. I’ve ordered a Dell Optiplex 3000 thin client N6005 which I will be using a ASM1166 m.2 to 6xSata adapter in a custom 3D printed case with 6 sata drives in a RAIDZ2 pool. Why? Because I want something low power for home lab use and it’s a fun project that I will document on my youtube channel. Don’t worry, I will document and post on here too so I can listen to a whole bunch of ridicule me on why I shouldn’t be dong that. Assuming I don’t get suspended or banned again, LOL.
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