Dell r720xd + H710P + 9211-8i

[truemooz]

Hi,

I figured this to be a general question I have, primarily for those that might own or might know a little more about the Dell r720xd than I do.

I recently just purchased this server to start a new home server setup. The server came preinstalled with the H710P RAID card which I've already flashed to IT mode to make it a software RAID card. I bought an addon rear flex backplane for the 2 rear HDD slots and have 2 SSDs in a RAID1, that is going to be OS/KVM hypervisor exclusive. I purchased a second RAID card (9211-8i) that I was planning to use exclusively for the front backplane, the backplane is the 12x3.5" HDD configuration that I was going to do a virtual hardware passthrough to a TrueNAS VM, so it will be completely 'independent' from the base OS that I have installed, this secondary RAID card was preflashed with the IT firmware to allow software RAID as well.

Generally, the question I'm starting to ask myself is if what I'm attempting to do is even possible with the r720xd. Has anyone attempted to do the same thing? I currently have the rear flex backplane hooked directly into the PCIe HBA. During POST, the HDDs are detected and it's suggesting that there are boot options there, but going through the BIOs and doing attempted OS installations seems to be going contrary to what the BIOS POST is telling me since aside from the 9211-8i saying it has drives attached to it, nothing else seems to believe it does. If I plug the rear flex backplane into the frontback plane, which I believe is supposed to be the 'Dell supported method of rear flex installation', the system boots fine.

Ideally, I don't even want the 9211-8i to be my OS boot card, I want to have my OS installed and RAID1 configured using the H710P and have all my data managed by the 9211-8i, but attempting to attach a SAS cable between the 9211 and the front backplane appears to not function at all..

Appreciate any advice/comments/suggestions in advance.

Thanks

 

[Alex_K]

Ok lets make it more clear

Double check what you crossflashing, with 2 controllers both of which cold be "touched" by same tools. Remove cache battery if crossfleshed H710P into IT and it had battery.

You install an OS onto rear drives. I'd go with ESXi, can't say about KVM, but should be possible too.

H710P is 2308 and a bit faster then 9211 which is 2008, but it wont be easy to saturate 2008 even if backplane uses only 1 connection of 4x6Gbps, and 2008 more stable.

Decide,
Option 1
If you want max speed then hook front cage into H710P in IT mode passthrough to TrueNAS VM, but boot from 9211-8i direct wired to rear cage.

Option 2
If you want max stability then hook rear cage into H710P in IR mode and install OS which can make use of cachecade and everything.
Connect front cage to 9211 and passthroug it to TrueNAS VM.


In no case where you install OS on rear drives you can hook there rear cage through front one but passthrough them separately.


Next, inside installed OS you should invoke various incantatios.. mean utilites like sas2ircu depend on OS to check if your OS see the 9211-8i and disks behind it.

9211-8i should be crossflashed to 20.00.07.00-IT, if you want to boot from it then you install ROM files too. You can install them anyways then disable loading them via BIOS setup to speed up boot. Check you have installed corresponding version for BIOS/EFI boot which you use.

 

[truemooz]

Ok lets make it more clear

Double check what you crossflashing, with 2 controllers both of which cold be "touched" by same tools. Remove cache battery if crossfleshed H710P into IT and it had battery.

You install an OS onto rear drives. I'd go with ESXi, can't say about KVM, but should be possible too.

H710P is 2308 and a bit faster then 9211 which is 2008, but it wont be easy to saturate 2008 even if backplane uses only 1 connection of 4x6Gbps, and 2008 more stable.

Decide,
Option 1
If you want max speed then hook front cage into H710P in IT mode passthrough to TrueNAS VM, but boot from 9211-8i direct wired to rear cage.

Option 2
If you want max stability then hook rear cage into H710P in IR mode and install OS which can make use of cachecade and everything.
Connect front cage to 9211 and passthroug it to TrueNAS VM.


In no case where you install OS on rear drives you can hook there rear cage through front one but passthrough them separately.


Next, inside installed OS you should invoke various incantatios.. mean utilites like sas2ircu depend on OS to check if your OS see the 9211-8i and disks behind it.

9211-8i should be crossflashed to 20.00.07.00-IT, if you want to boot from it then you install ROM files too. You can install them anyways then disable loading them via BIOS setup to speed up boot. Check you have installed corresponding version for BIOS/EFI boot which you use.

Hi there,

Thanks so much for your explanations, particularly about the different capabilities of the RAID cards I'm dealing with.

I think that Option #2 is what I'm going for. I understand technically from a OS and hypervisor standpoint what needs to be done, I think my confusion lies in how I'm supposed to be wiring the hardware.

Assuming that I have the 9211-8i connected into one of the PCI-e slots in Riser 1, where would I be plugging in my SAS cables to get the 9211-8i to be able to control the disks in the front backplane? Additionally, where would I be plugging in my rear rear backplane? Because, according to the Dell manuals, the rear flex backplane is intended to be plugged into the front backplane using a SAS cable into SAS-A1 port, and a pass-through I2C cable, please see the below link to get a more detailed view of what I'm referring to..as you can see, it doesn't specify any detail into avoiding the use of the H710P card in the removal / installation of the rear flex.

Dell PowerEdge R720 and R720xd Owner's Manual | Dell US

In case you might be wondering, the Dell R720 family has a proprietary-like SAS cable that is connected into the mainboard and plugged directly into the front backplane (cable shown in my second attached image). This cable and port on the mainboard is controlled using the integrated H710P controller.

Apologies if I wasn't more clear in my initial post.

Thanks in advance,

 

[Alex_K]

Well on cabling you may be better off if someone who had physical experience with the R720xd chime in.

I had no physical access to R720xd, but I know that they are wired a bit more complicated to the point when not even Dell support always know what is the difference between particular cables (see here https://www.dell.com/community/Powe...H730P-RAID-Controller-What-cable/td-p/4631550 )

On the other hand, I see no problem in connecting 9211 to the front backplane - literally any SFF-8087 - SFF-8087 cable should do, given length and angles are proper.

And BP SAS A /BP SAS B are the same type SFF-8087 you can connect directly to rear cage - if angles and length allow. It wouldn't be neat thought.