Critical error starting Guest after resizing memory to 16384Mb

[dbaslm]

I have a Red Hat 6.8 guest running on a Red Hat 5.11 host. The host has 32Gbytes of memory.

I can run the guest perfectly fine with 8192Mbytes of memory. I need to increase this as the guest is going to run Oracle 13c Cloud Control and this requires a minimum of 10Gbytes of memory.

I have set the base memory in the guest to 16384Mb and I get a critical error when starting the guest. I've also tried to start the guest with 12288Mb of base memory but again it fails to start.

Would it be a case that I need to increase the memory in the host above 32Gbytes to support guests that require more than 8192Mbytes of memory?

[mpack]

Please provide a VM log file. With the VM fully shut down, right click it in GUI. Select "Show Log" and save "VBox.log" (ONLY) to a zip file. Attach the zip here.

[dbaslm]

Log file attached.

[mpack]

Your guru mediatation error is "VERR_VMM_RING0_ASSERTION". This seems to have many potential causes, including the one you suggest.

Try increasing VRAM: I doubt that 12MB is enough.

It would be useful to see if you still get this error with a more current release of VirtualBox. Your log shows 5.0.26 (July 2016), the current release is 5.1.22.

Another workaround to try is mentioned in various tickets, e.g. https://www.virtualbox.org/ticket/15034

[dbaslm]

Many thanks, following the advice in that ticket I've set the following:

VBoxManage setextradata vmrhem01 "VBoxInternal/MM/CanUseLargerHeap" 1

This has allowed me to start the guest successfully.

Incidentally, I'm still on 5.0.x of Virtual Box as I tried to install 5.1.x but for some reason it wouldn't work on the RH 5.11 host. Gave up trying to find out why and have just stuck with the release I'm on. May try another upgrade.