Unsure how to accomplish hardware passthrough on a new server?

I recently came into possession of an R6525 which I want to get ZFS running on. It is a 1U server with 8 2.5 bays in the front. This comes with a PERC H345 front card. The card that it came with is detailed here: https://www.dell.com/support/manuals/en-us/poweredge-rc-h840/perc10_ug/perc-h345-front-card?guid=guid-34298b1d-9928-4f7f-9351-08244891d987&lang=en-us

I have had several Dell servers before, and typically when they come with a PERC card I just swap it out for an LSI card to do ZFS passthrough. In this case though, I’ve never had one of these and I don’t think that’s going to be an option here? The connector coming out of that front card goes directly back to the mainboard, and uses a connector I am not familiar with. Typically, I can just interface with the backplane and a cable will go straight into my LSI card, but in this case I don’t see a solution for that.

I don’t think the H345 can be crossflashed to IT mode, or if it can I don’t see how. The RAID utility doesn’t let me change the mode, and only supports a limited subset of RAID configurations. This is the newest hardware I’ve had and I’m not sure what the going solution is to this (other than to purchase an outstandingly expensive replacement PERC card which can be flashed.

Has anyone dealt with this before, and is there a solution I’m not seeing? I have an LSI 9211-8I available, but don’t know how I can get that to interface with this system?

Dell’s documentation is horrible, but it looks like it is RAID controller of sorts. So discard it and use a HBA is regular PCIe slot; you only need to figure out what is the connector on the backplane.

That was exactly my plan and I’ve done that in previous dell servers, and my LSI card would work perfectly, but I’ve never seen this interface before and have been unsuccessful searching for a name for it other than “PERC Cable”:

There are more details on page 64 here: https://dl.dell.com/content/manual23987793-dell-emc-poweredge-r6525-installation-and-service-manual.pdf?language=en-us&ps=true&dgc=SM&cid=376139&lid=spr7000897917&refid=sm_LITHIUM_spr7000897917&linkId=166002758

If I understand it correctly, the H345 cannot do passthrough, but the HBA345 CAN do passthrough, though it’s a large spend:

I’m thinking at this point that’s the shortest solution here.

Sorry for being chatty but I wanna be thorough in case someone else searches this info in the future.

This article has some interesting info; it suggests getting the HBA345 but then has steps to actually get the devices to be non-raid with the existing controller:

https://www.dell.com/community/en/conversations/poweredge-hddscsiraid/unable-to-set-up-passthrough-with-h345-controller/653bdd0035c28c5d4c07b269

I had to cold boot the system, go into F2 at boot, enter Device Options, find the RAID controller, configure it, then it had the option to convert to non-raid disks.

In my setup, that option is unavailable in the iDRAC UI:

This looks like “SlimSAS” SFF-8654, possibly the “8i” variety as it comes in various widths. What does it connect to?

It goes directly into the mainboard. The backplane has a socket on it that the entire H345 slides into, with the exposed pins on that card going in like a PCI slot, then the cable going from the H345 to the mainboard is similar to other SAS cables I’ve used with an L connector on one end and a straight one on the other, albeit with a different looking pinout. This is the cable: Dell 14NTK | PowerEdge R450 R650XS 8HDD SFF H345 H745 H755 SAS Cable - Serverworlds

Looks like SFF-8654 on both ends. [I corrected a typing a typing error in my previous post.]

So you need either a HBA with SFF-8654 8i connectors, which is likely to come a needlessly pricey PCIe 4.0 Tri-Mode, or find a 100 Ohm cable that is SFF-8654 8i to whatever the regular HBA needs (typically SFF-8087 for 9200, SFF-8643 for 9300).
Yep, these exist:

That is very helpful. Now that I found the config to allow “disable raid” I’m going to try to deploy an OS and see if I can see the raw disks, if not, I’ll tap in the LSI card and procure the cables. Thank you for the help!

For anyone else searching, you have to enter the lifecycle controller (F10 on boot) then enter device configuration, then actually enter the RAID card, and from within there you can choose disks and mark them as “Non-RAID” and you’re good to go. You can’t do it from the lifecycle controller itself, or the idrac, it has to be this entry which was very unintuitive. That being said, I’m getting direct write to the drives from the OS, and smart is showing all the correct attributes.

1 Like