Hi, I think the question # 2 might help you if you want to boot Nvme into BIOS mode.

 

https://www.dell.com/support/article/en-us/sln301149/frequently-asked-questions-regarding-nvme-solid-state-drives-ssds?lang=en

Q: What is NVMe?

A: Non-Volatile Memory express (NVMe) is a communications interface/protocol developed specially for Solid State Drives (SSD). Previously, Solid State drives used hard drive controller interfaces (SATA, SAS etc.) that were designed for spinning hard disk drives. NVMe (Based on the PCI Express data bus) standardizes the interface for SSDs requiring only 1 driver for all drives using this specification. (Similar to USB devices)

 

Q: Should I use NVMe drives with MBR?

A: No, Dell recommends NVMe drives be configured via UEFI & GPT for optimal performance, security and reliability.

 

Q: Is MBR the same as Legacy BIOS?

A: MBR refers to the Master Boot Record partitions of a hard drive. Legacy BIOS refers to system setup designs prior to UEFI. Both Legacy BIOS and UEFI allow you to configure the system options in the firmware of the motherboard. UEFI is intended to be used with the GPT partition type, but can be configured to use MBR on systems designed with Legacy BIOS support, but there are functional limitations and performance limitations associated with this legacy support.

 

Q: How are GPT and UEFI associated?

A:UEFI does not boot to MBR partitions without specific Legacy ROM support available in some Dell system UEFI setups. UEFI is designed for GPT partitions. Secure Boot will not function with a MBR partition.

Thanks for the fast response.

The NVMe SSD will be used as cache disk only and not to run an operating system off.

The NVMe will be mounted in the pre-installed OS (Debian) and mounted as cache disk to store images and the like for faster serving from the webserver.

We use the PERC H710p to boot from and the OS is already installed, but it failes to boot now because it was installed in BIOS boot mode and not in UEFI mode.

Question remains; why can't we change back from boot mode UEFI to boot mode BIOS (legacy) after adding the NVMe SSD? Even after removing the NVMe with adapter card from the server the changes are not saved aftre a reboot and the server switches back to UEFI boot mode. It looks like a bug in the BIOS.

Hello,

so if i well understand you cannot save any BIOS settings in the BIOS? Or just the boot mode?

Please can you try to reset the server and drain power?

Here the procedure (step3)

https://dell.to/3lqk6B8

 

Please let us know if it helps.

Thanks

Marco

Hi Marco, Thanks for your fast response. I've tried the power drain and the issue still persists. When entering the BIOS i can change settings and all settings are saved also after reboot. Accept for one crucial setting; the boot mode. When I boot into the BIOS and change the boot mode to "BIOS" and save, it replies the settings are saved and when I look back, before rebooting, the boot mode is indeed on BIOS. But... When I than reboot the sever, it stays in UEFI boot mode. So it seems only the boot mode settings is not saved, the rest is. This issue started directly after installing the PCIe NVMe adapter and M2. SSD. The very first boot after installing the NVMe card the service immediately switched from the boot mode BIOS, which was previously already selected and never changed, to UEFI. So it seems the adding the NVMe hardware to the PCIe slot, forces the boot mode into UEFI and after that there is no way to return to the BIOS (legacy) boot mode. Even with the card completely removed, the bios reset, iDRAC reset, power drain and so on. Even tried to flash the bios firmware with the /wipeclean parameter. The update succeeded but it did not solve the issue.

Hello,

can you try also to clear BIOS using the motherboard jumper?

Here the procedure:

https://dell.to/2Jnd5DX

 

If it doesn't resolve probably there is an issue on the motherboard, if you already remove the card.

Also try to remove unnecessary device keeping server only with:

 

- System board

- CPU

- Single Dimm in socked A1

- Expansion Riser

- PSU

 

Let me know thanks

Marco

 

 

 

@DELL-Marco B 

Thanks again for your response.

Tried all options you mentioned with no success.

We have switched our OS (Debian) from BIOS boot to UEFI boot mode and it is up and running again. The server boots normally and there are no error logged to the OS log nor the Lifecycle Log.

But the issue is not resolved. We have 2 other R420 machines that we are planning to install the NVMe disks in. Except we do not want to face the same results.

Therefor i ask you if you can try to reproduce this on your side with an R420.

This are the steps to perform the test:

- Install base OS; Linux or any other in BIOS boot mode on an R420.
- Add 1 PCIe NVMe adapter with 1 NVMe m.2 stick. We use a Samsung, but any M.2 NVMe will do i guess.
- Boot the machine and see if it stays in BIOS boot mode, or switches automatically to UEFI.

There are 2 possible outcomes:

1. If it changes to UEFI boot mode on your side too, it most likely is a software issue in the BIOS.
2. If is stays on BIOS boot mode, it is most likely an issue on our side.

What surprises me the most is the conclusion that it must be a hardware issue. The machine works fine and no errors are shown in the Lifecycle log or the OS log. Bios changes are saved, accept the boot mode option after installing an NVMe ssd. My conclusion remains that it must be a software issue with the firmware of the BIOS.

Can you please try to reproduce the issue on your side and report back to let me know the outcome?

Looking forward to your response.

Thank you and best regards.

Hello,

i'm sorry but I cannot test your configuration in a labo environment.

My conclusion about hardware issue is when you said that even without NVMe adapter installed BIOS setting cannot remains in legacy bios mode, that it is not normal.

You said that firmware are updates, but BIOS also is at the last version?

It could be also a compatibility issue with the NVMe adapter, did you buy with a Dell order?

Thanks

Marco

 

Hi,

My last post disappeared? Where did it go?

I'm using a Samsung m.2 NVMe stick inside an plain PCIe to NVMe adapter. Not ordered by Dell, but that should not make any difference. It's brand new hardware.

The fact that one specific BIOS setting is not saved after installing and removing a card to the server should be the mainboard failing just does not sounds very logical. If something is broken, it does not work at all, but the hardware works fine after installing it in UEFI mode. The NVMe card also works as expected and so does the rest of the server. Only issue is that the boot mode cannot be set to BIOS anymore. This seems like a software issue to me.

The amount of time spent to this issue is crazy. Rebooting, waiting half an hour before the machine comes back up, just to see that the issue is still there. When I then ask Dell to perform a test they refuse. That's was not the feedback I'd expect. I performed all test you asked me. Why not test this on your side? Because it's old hardware? I don't get it sorry.

And whats up with the captcha? I have to fill in 10 instances, what is this some sort of game?

Hello,

I'm sorry you are experiencing this kind of issue. 

I'd have been more than happy to do this type of test if I had had the same hardware but unfortunately we don't have this type of hardware in the lab.

I can tell you also that this is not a known issue and in our internal knowledge base there are not similar behaviour. 

Did you also tried with the NVMe adatper insterted but without the NVMe stick?

Thanks

Marco