BIOS RAID Settings

Hi all, after having some semi regular, but minor issues with some Intel Enterprise SSD’s connected to the SATA ports on my X399 Prime-A motherboard, I began to wonder if I have misunderstood the motherboard RAID setting all along and perhaps it is actually better to enable it for software raid systems such as ZFS. I have been brought up in the school of these are only for doing some weird motherboard sudo / hardware / software raid with windows drivers made by the motherboard manufacturer and therefore have always avoided it (as such they are all set to AHCI). I haven’t been able to find anything concrete from searching. I was thinking perhaps disabling AHCI and enabling RAID mode in the BIOS perhaps hands over some of the SATA instructions to ZFS (or other equivalent raid systems) that would normally be handled at the hardware level or something. Indeed there is no ability to set up RAID arrays in the BIOS. Does anyone know? Thanks.

Don’t do this. Leave AHCI mode enabled or really bad things will happen to your data.

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So do you have any insight as to what enabling raid mode in the bios actually does? Given it doesn’t actually create a raid array - I have begun to wonder if you should actually turn it on. I’m looking for evidence, not just opinion. I already had your opinion for many years, I am second guessing myself as due diligence. I know I’ve seen some bioses that did have raid creation stuff in the bios, this one doesn’t. It’s a threadripper board BTW.

Why though?

Your motherboard manual explains the difference.
Page 3-13 in the English version.

As you can read for yourself, it explains that some performance features are enabled if it’s set to AHCI. I’ll also note that things like Hot Plug and Secure Erase are only available if AHCI is enabled.

Don’t do this.

I am not sure what setting it to RAID and then not configuring any volumes would actually accomplish. My guess is that unless you configure it further, your motherboard treats them as individual disks until you configure it otherwise, sometimes referred to as JBOD. This adds a translation layer that would not exist if it was set to AHCI.

But by the sounds of it you may be set to let try this either way, please feel free to let us know how it went. Page 4-2 explains how to access the RAID configuration utility.

Good luck.

I have read the motherboard manual already, it is why I am coming here asking questions. But since you raise it, in particular two points as per screenshot from the manual below:
1 - “AHCI enables features by allowing the drive to internally optimise the order of commands” - I was thinking with software raid, possibly these commands should be handed back to ZFS (not knowing at all what these commands are of course and hence my question)
2 - “Set to raid when you want a raid configuration from the SATA hard drives”, which is generic enough to apply to ANY raid configuration, not just some funky bios raid - again, this is why the question. Initially your above responses didn’t seem to provide any further information than what I already learned over the years. Saying ‘don’t do this’ didn’t really answer it and you also used the phrase ‘my guess’ which didn’t install confidence (not having a go here, just trying to get to an evidential answer rather than an educated guess).

Also, I am not keen on just changing this setting to see - despite having full off site backups and non time critical data. I’m just keen to stop these occasional errors.

All in all, it was my reading the manual that made me suspicious because of point 1.

Apologies if any of the above sounds offensive, it is not my intention, I am unsure how else to ask for the specifics, rather than the beliefs. Because as I said before, my beliefs have always been exactly as you describe around this, but we are not good engineers if we don’t question things from time to time and be open to having been wrong - or perhaps the meaning of BIOS raid changed over the years etc.

Taking on board your point of the Raid utility in the manual though, the first part lends itself to being open to interpretation, but eventually it does talk about needing a RAID driver for windows, which aligns more with what we both have learnt over the years, and thanks because I hadn’t noticed / nor read that part.

If anyone else knows any different, or in particular what SATA commands are disabled by setting the BIOS to raid mode (and anything else that happens), I’m still keen to understand. This gives me more to think about and I am going to see if I can dig a little deeper into the tech now anyway to see if I can understand what it’s doing more.

Thanks for your help.

Marshalleq

Vague specifics; any form of raid changes how the drives are presented to zfs. Zfs needs full access to the drive else things will eventually go wrong & likely read to data loss.

There have been multiple examples of folks that ran zfs ontop of raid & eventually led to data loss.

For real specifics, beyond my very poor understanding/explination, you’re instead going to need to read in on why zfs needs direct access to drives (basically how zfs works on a low level) & how raid might present drives & restrict access to said drives (basically how your flavor of raid works on a low level). Then you’ll want to review why they aren’t compatible with your knowledge of how they both function. With this understanding on why water & oil don’t mix on a chemical level, you’ll then actually have an educated opinion on the matter.

Otherwise all you’ll get are basically repeats of the same info I just said, and you’ll have to trust that they don’t mix.

Up to you if it is worth investing the time to learn that much about both. For me, I’ve seen enough examples of folks who forgot to flash an HBA to IT mode & made their pool zfs pool on a raid array & the nightmares they faced that I don’t feel the need to question it.

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That sounds like Native Command Queuing (NCQ), which is a feature supported by Advanced Host Controller Interface (AHCI). There was a time when one could choose IDE oder AHCI for SATA devices in BIOS.

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and

Yes, this was at the heart of my question, because yes I’m aware and due to my issues I was wondering if the RAID setting actually did this better. Though hearing the above from you, provided that at least one of those examples was BIOS software raid i.e. confirms that the bios raid is similar to what you’d get on an actual RAID card, which again, we already know it isn’t - but it seems to be a grey area.

I think you’re barking up the right tree though, because what I should be looking for is how ZFS takes advanced AHCI SATA commands vs IDE. From what I’ve read (since my last message), it seems RAID mode basically turns the SATA port back into IDE mode, from long ago rather than actually performing some nefarious BIOS array creation. Which continues to make me wonder, WHY does a motherboard manufacturer think running SATA in IDE mode is better for RAID or put another way, why do they think not running the advanced AHCI SATA commands are better? This comes to the heart of my question and wondering.

So unless you’re saying you saw examples of folks having issues running ZFS on top of the RAID type set in BIOS (but not formatted by the motherboard utility), I’m still missing an answer I think.

Another point is, that I ‘assume’ that others are running ZFS atop of AHCI without issue and again assuming that this is not simply the boot drives and are drives with high read/writes going on such as what I have, which tends to speak for itself - but too many assumptions for my liking. Nevertheless assuming all of that, I suppose it’s possible to have multiple of my enterprise drives failing with unrecoverable data (not unrecoverable pool, just those specific disks) simultaneously, but it does strike me as unusual. They are nice Intel 480’s but they are getting older now. Nevertheless it may be as simple as that. And given I haven’t found any actual answers yet, I will keep looking and report back if I do find anything.

It does appear non command queuing and hot plug are disabled, which is interesting if the BIOS raid is disabling hot plug.

Thanks.

Yeah, from some small reading I did today, it seems to be that RAID mode is nearly the same as IDE mode just renamed. I say nearly only because I haven’t confirmed that it’s all - and it does need a driver for windows - which I assume native IDE wouldn’t, unless that’s now a removed feature.

I am pretty sure it needs a driver, too, but that comes shipped with windows or works with a standard windows driver, whereas special raid drivers do not.

I am curious to see what you find, because I’ll be honest I have no clue where to event look!

I wrote a lot, skip to the bottom for my answer.

As @Fleshmauler has indicated, ZFS requires direct access and full control over the drives to do its job of ensuring each drive has the proper data and no errors on any single drive. Using a RAID defeats this ability for ZFS will be shown a single drive, not multiple drives to check data against. So, while you could get a server up and running on TrueNAS while using a RAID, when your motherboard craps out, the drives have data that doesn’t match, any one of many thing that software ZFS protects you from, you are going to be asking for help and you are likely to hear that you should not have used a RAID with ZFS. Another thing to consider, will that RAID tell you when a drive is starting to fail? Tell you a drive did fail? And how will it do that?

The ONLY place where you can use a hardware RAID is for the boot drive. Having a RAID 1 for the boot drives means your system “should” still boot if one drive becomes corrupt. That isn’t always true, if your system starts to boot off of drive A and gets half way into it and crashes, locks the machine up, well drive B isn’t helping you. It’s a risk but if you have a mission critical device, a RAID for the boot drives makes sense. So you say, Doesn’t TrueNAS allow you to have two boot drives as well? the answer is yes it does. The big difference is, many motherboards will only boot from a specified drive and so long as that drive appears to be bootable, it will not fail to the next drive in sequence. So basically the drive either needs to not have a boot partition or no power to roll to the second drive. A RAID handles this significantly better, both drives are considered a single drive to the motherboard only needs to boot from the RAID and the RAID decides the good drive. It isn’t fool proof but it is a better option than a boot mirror if you are mission critical. I’m sure some IT folks would argue it isn’t that big of a deal, but if it were your home system and you are on a trip, the system crashed, your significant other is complaining he/she can’t access something, which one would you want? I have run a RAID for boot drives, just for the experience, but for my home system, it isn’t a big deal. One boot drive, maintain a copy of your configuration files, restoration is a breeze.

So the answer is: Do not use RAID if you plan to use ZFS, unless it is only for the boot drives.

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I think, the idea is to just set the SATA controller to RAID instead of AHCI in the BIOS of the (consumer) mainboard, hoping these settings are better suited to it being used with any type of raid, be it from the mainboard manufacturer or in this case, ZFS.

With an Intel board you’d find this ability after you’ve bought a VROC key to turn your chipset into a (limited) hardware RAID controller. With an AMD board, I have no idea.

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@prez02 said it best. Some people are jumping in with out reading or perhaps understanding - I am not suggesting to use a kind of raid array underneath zfs.

I am suggesting that the raid mode set against an sata port may in fact work better for zfs as perhaps it gives it more control or as the data seems to suggest it’s effectively running the disks in ide mode which the motherboard manufacturers seem to think is better for when you do run any type of software raid I hope that clears it up. Telling me not to run zfs on hardware raid - I already know this, it’s obvious. Thanks for trying to help though.

Go with AHCI, you will never have an incompatable interface should you require to replace your motherboard.

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You don’t want a raid configuration when you are running ZFS. Issue solved :slightly_smiling_face:

If you want to delver more on the motherboard specifics you should perhaps ask your motherboard’s technical support, or move this thread into General Discussion.

Please read the thread properly before replying.

It seems like you missed the point of the thread.

I didn’t think I did, however I’d like for you to avoid the possibility of setting up a RAID if you are going to use TrueNAS. This forum is about TrueNAS and while we have no problems looking into other things such as a motherboard RAID and how it works, you are going to see people try to steer you into the right direction so you can minimize data loss. That is what most of us long time member do. We do not do it out of malice or to irritate someone.