Linux VM Guest doesn't recognize more than 64GB RAM

Discussions related to using VirtualBox on Mac OS X hosts.
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jvega
Posts: 3
Joined: 16. Feb 2018, 23:19

Linux VM Guest doesn't recognize more than 64GB RAM

Post by jvega »

Hello,

I'm trying to create a Linux VM with 64GB (or 80GB) of RAM. But when I configure the VM to use the 64 or more GB, the Guest OS is only recognizing 3.4GB. It doesn't happen if I configure the VM with 48GB or less.

I'm using VirtualBox version 5.2.6 r120293 in a Mac Pro (Late 2013) 3.3 GHz 8-Core Intel Xeon E5 and 96GB RAM with Mac OS 10.13
The Guest OS is an Oracle Linux 6 update 9 with uek-kernel 4.1.12

Any idea of why this can be happening?

I tried to verify if VM's with more than 64GB RAM are supported, and I have not been able to find any limitation about it. So not sure if this is really supported.
socratis
Site Moderator
Posts: 27329
Joined: 22. Oct 2010, 11:03
Primary OS: Mac OS X other
VBox Version: PUEL
Guest OSses: Win(*>98), Linux*, OSX>10.5
Location: Greece

Re: Linux VM Guest doesn't recognize more than 64GB RAM

Post by socratis »

We're going to need to see a VM log from a complete VM run:
  • Start the VM from cold-boot (not from a paused or saved state) / Observe error / Shutdown the VM (force close it if you have to).
  • With the VM completely shut down (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log".
  • Save only the first "VBox.log", ZIP it and attach it to your response (see the "Upload attachment" tab below the reply form).
Also, the "recipe" of the VM, the ".vbox" file:
  1. Right-click on the VM in the VirtualBox Manager. Select "Show in Finder/Explorer/Whatever".
  2. ZIP the selected ".vbox" file and attach it to your response.
Do NOT send me Personal Messages (PMs) for troubleshooting, they are simply deleted.
Do NOT reply with the "QUOTE" button, please use the "POST REPLY", at the bottom of the form.
If you obfuscate any information requested, I will obfuscate my response. These are virtual UUIDs, not real ones.
jvega
Posts: 3
Joined: 16. Feb 2018, 23:19

Re: Linux VM Guest doesn't recognize more than 64GB RAM

Post by jvega »

I was able to fix the problem, initially I was booting with the UEFI firmware,

I tried again installing the OS with BIOS booting, after that, the 80GB RAM were recognized, looks like the problem is with the UEFI firmware.
socratis
Site Moderator
Posts: 27329
Joined: 22. Oct 2010, 11:03
Primary OS: Mac OS X other
VBox Version: PUEL
Guest OSses: Win(*>98), Linux*, OSX>10.5
Location: Greece

Re: Linux VM Guest doesn't recognize more than 64GB RAM

Post by socratis »

jvega wrote:looks like the problem is with the UEFI firmware.
That may very well be. There were/are several issues with the memory passed to the OS, if it's booted with EFI. As it's becoming more prominent, I can only see improvements. But not until it becomes mandatory to use it. And right now it's only mandatory for OSX guests...

Just one question; did you enable EFI and ICH9 at the same time of the failure?
Do NOT send me Personal Messages (PMs) for troubleshooting, they are simply deleted.
Do NOT reply with the "QUOTE" button, please use the "POST REPLY", at the bottom of the form.
If you obfuscate any information requested, I will obfuscate my response. These are virtual UUIDs, not real ones.
jvega
Posts: 3
Joined: 16. Feb 2018, 23:19

Re: Linux VM Guest doesn't recognize more than 64GB RAM

Post by jvega »

I tried with both chipsets ACH9 and PIIX3.
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