Best with RAID controllers or RAID-Z software

[WhiteTiger]

I have an old Dell server with SAS controllers and 8x300GB and 2x160GB HDDs. I can handle RAID 0, 1, 10, 5, 50.
I am undecided how to configure the disks and in general also on other servers if it is better to use the controller RAID or configure RAID/RAID-Z from TrueNAS.

On this server I was thinking of using the controller for RAID1 on the two 160GB disks and the other disks with RAID-Z2/3.
The server has 8GB of RAM, performance is not as important as data reliability.
Thanks in advance for the advice.

 

[Etorix]

If you seek reliability, do NOT use hardware RAID of any form. Flash your controllers to IT mode and let ZFS handle everything from top to bottom.

What's all the noise about HBAs, and why can't I use a RAID controller?

1) An HBA is a Host Bus Adapter. This is a controller that allows SAS and SATA devices to be attached to, and communicate directly with, a server. RAID controllers typically aggregate several disks into a Virtual Disk abstraction of some sort...

www.truenas.com

 

[WhiteTiger]

If you seek reliability, do NOT use hardware RAID of any form. Flash your controllers to IT mode and let ZFS handle everything from top to bottom.

I don't know how to flash the controller.
Isn't it enough to turn off hardware RAID to see all disks individually?

 

[QonoS]

I don't know how to flash the controller.
Isn't it enough to turn off hardware RAID to see all disks individually?

That should work too but should be your last option. Try setting the controller to HBA or IT mode first.

 

[Evertb1]

I don't know how to flash the controller.

There are a number of guides to find on the web about flashing a HBA to IT mode. The page on this link will guide you trough the flashing of Dell Perc H200 and Dell Perc H310 controllers. I used this guide my self a couple of times and it did not fail me yet. Just read it from top to bottom to get an idea what you are dealing with and then execute the instructions. It's not hard. If your controllers ar not Perc H200 or Perc H310 this instructions might still work if your controllers are based ont the LSI-9211 chipset.

 

[WhiteTiger]

OK thank you.
But can you tell me what it means to flash it on the controller and why do it?

 

[Evertb1]

OK thank you.
But can you tell me what it means to flash it on the controller and why do it?

The controller is a Microprocessor in it's own right. Just like any computer it needs software to make it perform it's functions (executing instructions). In this case the program with instructions is called the firmware. That firmware is not stored on a disk but on a special chip. With flashing you can replace the current set of instructions for a different set of instructions in that programmable chip. TrueNAS and it's predecessor FreeNAS works with the ZFS file system. That works best when ZFS has direct control over the to the pool assigned disk(s). By flashing the controller to IT mode you basically put it in pass trough mode so it stops working as a raid controller. And that's the way ZFS likes it.

 

[ChrisRJ]

That should work too but should be your last option. Try setting the controller to HBA or IT mode first.

This is pretty risky advice. Even if the controller offers these modes, they are very likely not the same as direct access to the disks. Also "should work" is not a good basis for giving advice, quite honestly. I don't want to be rude or patronizing, but there is a reason why people are told to use either on-board standard SATA port (in AHCI mode) or an LSI-based HBA in IT mode. And that reason is the risk that comes with other approaches. Risk does not mean that disaster will strike. But with valuable data (and if the data were not valuable, why use something like TrueNAS in the first place?) taking such a risk rather than buying such an HBA (usually for roughly USD/EUR 50) is highly questionable.

 

[QonoS]

This is pretty risky advice. Even if the controller offers these modes, they are very likely not the same as direct access to the disks. Also "should work" is not a good basis for giving advice, quite honestly. I don't want to be rude or patronizing, but there is a reason why people are told to use either on-board standard SATA port (in AHCI mode) or an LSI-based HBA in IT mode. And that reason is the risk that comes with other approaches. Risk does not mean that disaster will strike. But with valuable data (and if the data were not valuable, why use something like TrueNAS in the first place?) taking such a risk rather than buying such an HBA (usually for roughly USD/EUR 50) is highly questionable.

It seems you are not familiar with certain Dell SAS Controller. These do not need to be reflashed (which is a risky operation itself). These can be run in RAID or HBA mode. In HBA mode they do not lack anything compared to any other HBA controller. If the controller in question offers "HBA mode" there is no need to flash, reconfiguration is the best choice.
If you are interested here is a short video about reconfiguration: https://www.youtube.com/watch?v=l41rhE79vqU

Apart from that is a HBA around USD/EUR 50 "questionable" for "valuable data" in my eyes.

Thanks for your reply but in this case I have to reject your critic.

So all in all I see 3 options here starting with the best:

1. reconfiguration to HBA mode (if supported by controller)
2. reflash (if possible)
3. Continuing with RAID mode and leaving disks unconfigured. I do not recommend that but it is an option.

 

[Evertb1]

f you are interested here is a short video about reconfiguration: https://www.youtube.com/watch?v=l41rhE79vqU

Interesting option. Though I do wonder how likely it is that an old Dell server is equipped with a Perc series 9 controller or higher. I think it should be at least from 2014-2015. It would help if the OP let us know if he was able to identify his controllers.

 

[Constantin]

Given the very low cost of a quality, genuine used LSI HBA that has already been reflashed to IT mode, my suggestion for anyone who feels uncomfortable doing so themselves is to find a quality reseller on eBay and letting them take care of all that. Several have been listed in this forum, across multiple geographies.

For me, it comes down to how much my time and data is worth. Hence, I have a LSI HBA, no reflash required, it works perfectly in IT mode, and I'm as happy as a clam.

 

[HoneyBadger]

In HBA mode they do not lack anything compared to any other HBA controller.

Careful, you'll get the Grinch coming down if you keep that up.

You'll potentially (likely) be running the mrsas driver instead of the better-tested mpr or mps driver.

Because of this, the options in my mind, and many others here, are, in order:

1. Buy an official genuine LSI HBA, avoiding third-shift Shenzhen knock-offs
2. Crossflash your IR/OEM HBA with LSI firmware
3. Use the built-in "HBA Mode" but only if you're using an LSI HBA that loads mrsas, if you're on a ciss/aacraid/etc driver then buy an HBA
4. Use individual RAID0s and prepare for potential data loss if the firmware/driver sucks

Note that #3 and #4 are very likely to garner a response of "why didn't you do #1 or #2?" if/when a question is posed on the forums.

 

[jgreco]

It seems you are not familiar with certain Dell SAS Controller. These do not need to be reflashed (which is a risky operation itself).

We are actually quite familiar with certain Dell SAS controllers. You are entirely correct that they do not need to be reflashed, they should be yanked and replaced instead.

When you replace it, you will want to replace it with a real HBA, not a pseudo-HBA. This is specifically called out in the article at

https://www.truenas.com/community/r...bas-and-why-cant-i-use-a-raid-controller.139/

and is covered extensively in points 3), 4), and 5).

YOU WANT A REAL HBA RUNNING LSI IT FIRMWARE.

3. Use the built-in "HBA Mode" but only if you're using an LSI HBA that loads mrsas,

mrsas isn't particularly recommended, but is much better than mfi was. We could use lots more guinea pigs for current mrsas, the failures with it to date haven't been particularly clear as to why things went wrong.

 

[Evertb1]

Well, strong opinions are not uncommon on this forum. Nothing wrong with that. You can learn a thing or two if you are willing. But maybe we should wait now until the OP tells us what hardware is owned by him or her.
@WhiteTiger: Please inform us about your system. Communicating what hardware you own is part of the Forum rules. You can read the rules by clicking on the "Forum Rules" link at the top of this page. Edit your original post and add the information about your hardware according to the list presented in the rules. That way you can expect much better help and/or advice.

 

[titust1]

If you seek reliability, do NOT use hardware RAID of any form. Flash your controllers to IT mode and let ZFS handle everything from top to bottom.

What's all the noise about HBAs, and why can't I use a RAID controller?

1) An HBA is a Host Bus Adapter. This is a controller that allows SAS and SATA devices to be attached to, and communicate directly with, a server. RAID controllers typically aggregate several disks into a Virtual Disk abstraction of some sort...

www.truenas.com

Why are you saying that? What's wrong with HW Raid reliability? I don't get, I used HW Raid on servers for years in the enterprise....

 

[danb35]

What's wrong with HW Raid reliability?

If you'd read the link you quoted, you'd have your answer. If questions remained after doing so, you'd be better off asking in the discussion thread there. But the short answer is, you probably didn't use ZFS on those servers for years in the enterprise.

 

[titust1]

If you'd read the link you quoted, you'd have your answer. If questions remained after doing so, you'd be better off asking in the discussion thread there. But the short answer is, you probably didn't use ZFS on those servers for years in the enterprise.

I was not talking about HW Raid in the context of ZFS and Truenas (I know that's not possible), I was talking about HW Raid in general, instead Truenas and ZFS. It's another choice isn't it, and it's pretty reliable? At least a Raid5 I can grow it by adding a drive to it, a RaidZ1 I can't. I have to delete the pool and recreate it. That's still pre-historic about ZFS. I hate that

 

[danb35]

I was not talking about HW Raid in the context of ZFS and Truenas (I know that's not possible)

Then your comment really doesn't have anything to do with this forum, does it? Particularly to revive a long-dead thread to post it?

 

[Constantin]

Why are you saying that? What's wrong with HW Raid reliability? I don't get, I used HW Raid on servers for years in the enterprise....

They work great, until they don’t and then you get to nuke the array and start over. *Hopefully* your data didn’t get silently corrupted in the meantime, leading to even your backups being randomly screwed up. I didn’t get a t-shirt when my XFX hardware RAID card did that to me.

Hardware RAID may be fast, convenient, and very simple to use, but it doesn’t even come close to ZFS in terms of reliability / data corruption prevention. Hence also the much stricter suggested hardware requirements for ZFS systems like ECC RAM or a much smaller list of known-good HBAs and associated drivers, for example.

Comes down to how much you value your data. Nothing wrong with choosing RAID per se but know the risks. I chose ZFS for long term storage since Apple continues to ignore bit rot.

 

[Etorix]

I was not talking about HW Raid in the context of ZFS and Truenas (I know that's not possible), I was talking about HW Raid in general, instead Truenas and ZFS.

And the comment you quoted above was strictly in the context of using ZFS, so all should be fine ;)