So today I installed truenas 25.10 on a Dell PowerEdge 2950 which has a PERC 6/i raid controller connected to the internal backplane. I read in a thread on reddit ( /r/freenas/comments/bbpmm2/r610_perc_6i_jbod/ ) that I can ignore setting up a raid on the card and just pass the disks through to freenas using tunable variables. This did not work.
So I got the idea to install something a little more contemporary to the post on reddit. I went with 11.3U5. Added the tunable variables, hw.mfi.allow_cam_disk_passthrough and ya know what? It worked perfectly.
Can someone please tell me how to replicate this behavior in the current version of truenas?
Safe answer is to install a HBA card.
What’s all the noise about HBA’s, and why can’t I use a RAID controller?
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Some Dell Perc controllers are standard LSI HBAs, and can be flashed with an LSI firmware to make them operate in “IT mode”. Unfortunately I don’t think the 6/I is one of them. Also, that’s a PCI1.0 card and only supports 3Gb/s, so will be pretty slow,
I’d get another HBA, as @SmallBarky recommended.
That said, I’ve run into a particular problem with Dell PowerEdge hardware you might want to look out for: I had a server with a built-in modular Perc HBA that couldn’t be operated in IT mode. I put a different HBA in (and LSI9211) and hooked up the internal drive cages in the server to the new HBA, but the server wouldn’t POST. The onboard HBA failed it’s tests when it couldn’t see the drive cages, even when it was disabled.
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Right. Which is why I don’t want to waste my time and money getting an HBA that doesn’t work.
Also, I’ve flashed nothing into IT mode. This is just how things seem to work with 11.3U5. So if it works with 11.3U5 there should be a way to get it to work in 25, right? I realize it isn’t freebsd based nowadays but that doesn’t seem like it should matter.
If it isn’t a capability of the software any longer than that would be nice to know. It seems weird that it recognized the tunable as valid still if it isn’t. Either way, this is the hardware I have and I’m trying to make the most of it.
Also, of this isn’t the right place to ask this question, please let me know that, too. I’d rather ask this in the right place then have a bunch of people who don’t know look at this.
The tunable you used is a FreeBSD one to override the old mfi driver to let it do blind disk passthrough. There’s likely something similar for Linux, but the better answers would be to 1) reflash your PERC 6/i into its LSI equivalent based on the SAS1068E chip, or 2) upgrade to a newer card, because that card is SAS1 and has limitations from that era (2TB drive capacity, no 4Kn support)
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Re. point 5 in the article @SmallBarky linked to: a RAID controller in JBOD mode (what you almost certainly have) is not the same as an HBA in IT mode.
There are considerable performance and reliability gains to be had running in IT mode.
As to why it worked on FreeBSD and not linux, it’s almost certainly a driver thing as the adapter is so old.
It looks like Redhat removed driver support for it sometime ago, I suspect Debian (which Scale is based on) did the same:
https://www.reddit.com/r/RockyLinux/comments/v1db4q/rocky_linux_installer_not_recognizing_perc_6i/
Thank you for that last bit. As for jbod mode vs it mode, the card isn’t running in jbod. It doesn’t even support that. It is completely unconfigured. The driver thing makes sense either way.
I think what I’ll probably do is run the card with 2 raid 5 arrays and then run a striped vdev on the truenas side.
I would strongly advise against that.
ZFS really likes having direct access to the disks it’s managing, which is why RAID controllers running in JBOD mode (which I know you’re not doing) aren’t recommended. Doing hardware RAID on the PERC adapter, then software RAID on top of that is a recipe for low performance and data loss.
Do this at your own risk.
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Okay, well then I will find an os/software combo that offers a nice web interface for controlling network shares and containers. If you know of any good alternatives that will do nearly everything truenas does without the need to use zfs please let me know. I’d really appreciate it.
Have a look at Open Media Vault
