VirtualBox

Opened 15 years ago

Last modified 11 years ago

#3069 closed enhancement

Feature request: support more than 3.584 MB guest RAM (64 bits hosts) — at Version 25

Reported by: Patrick Julien Owned by:
Component: host support Version: VirtualBox 2.1.0
Keywords: memory Cc:
Guest type: other Host type: Windows

Description (last modified by Frank Mehnert)

Even when running the 64-bit version of VirtualBox on a 64 bit version of Windows Vista, it's not possible to allocate more than 3GB of memory to the guess operating system.

Change History (24)

comment:1 by Frank Mehnert, 15 years ago

Summary: Guest memory limit on Windows 64 bit host is still 3GBGuest memory limit is 4GB (even on 64-bit hosts)

comment:2 by Sander van Leeuwen, 15 years ago

Resolution: worksforme
Status: newclosed

Which method are you using for running the VMs? My VirtualBox.exe has the LARGE_ADDRESS_AWARE flag set and I can use up to the max (3.584 MB). Vista 64 host with 16 GB ram.

comment:3 by Patrick Julien, 15 years ago

I too, can set the maximum to 3.584MB with a Vista 64 bit host with 32GB of RAM.

However, it's possible for the process to access up to 8TB of virtual address space. Looking at the article that I posted, the testlimit64 tool was able to reserve(not commit) 8TB of virtual memory before running out.

I am trying to find the switch that makes this possible.

comment:4 by Patrick Julien, 15 years ago

According to the information I have found, IMAGE_FILE_LARGE_ADDRESS_AWARE is all that is needed on a 64-bit host to have access to an 8TB address space on 64 bit.

So why is virtual box limiting the memory limit of a guest to 3.584MB then?

comment:5 by Sander van Leeuwen, 15 years ago

Because we don't allow more at the moment. That has nothing to do with executable image flags. We will allow for more in the near future.

in reply to:  5 comment:6 by Patrick Julien, 15 years ago

Replying to sandervl73:

Because we don't allow more at the moment. That has nothing to do with executable image flags. We will allow for more in the near future.

OK then, sounds good.

comment:7 by Sander van Leeuwen, 15 years ago

priority: minormajor
Summary: Guest memory limit is 4GB (even on 64-bit hosts)Feature request: support more than 3.584 MB guest RAM (64 bits hosts)

comment:8 by Sander van Leeuwen, 15 years ago

Note that we'll probably not implement this on 32 bits *hosts*.

comment:9 by Sander van Leeuwen, 15 years ago

Description: modified (diff)

in reply to:  10 comment:11 by Patrick Julien, 15 years ago

Replying to pjulien:

Replying to sandervl73:

Note that we'll probably not implement this on 32 bits *hosts*.

I wouldn't expect you too, this is a feature request for 64 bit hosts only.

comment:12 by Patrick Julien, 15 years ago

However, I have to ask why did you close this "worksforme"? Shouldn't this ticket be left open and turned into a RFE?

comment:13 by Sander van Leeuwen, 15 years ago

Resolution: worksforme
Status: closedreopened

comment:14 by Sander van Leeuwen, 15 years ago

Of course. Forgot :)

comment:15 by Sander van Leeuwen, 15 years ago

Type: defectenhancement

comment:16 by bqbauer, 15 years ago

2.1.2 says you can now have up to 75% of host memory in new guests. I've tried creating a new 64-bit guest on my 64-bit OpenSolaris host with 8GB memory, and the limit is still 3584. Also tried a larger number using VBoxManage, and it also says the limit is 3584.

comment:17 by Nikolay Igotti, 15 years ago

More than 3.5G RAM limitation for guests not yet lifted - it's hypervisor limitation. Mentioned feature is only UI enhancement.

comment:18 by Scott Pakin, 15 years ago

I just want to chime in that enabling 64-bit guests to access more than 3584 MB of memory on a 64-bit (Linux) host containing gobs and gobs of memory is highly desirable to me as well. Any chance the hypervisor limitation will go away sometime soon? (I have no idea how much effort is involved in getting the hypervisor to handle large memory spaces.)

comment:19 by Frank Mehnert, 15 years ago

Resolution: fixed
Status: reopenedclosed

Fixed with version 2.2.0, make sure to check the latest release 2.2.2. VirtualBox can now maintain up to 16GB on a 64-bit host.

comment:20 by Scott Pakin, 15 years ago

Thanks, but why is there any limitation other than what the CPU can address? Can't VirtualBox be modified to support an "infinite" amount of guest RAM?

comment:21 by Frank Mehnert, 15 years ago

The guest RAM has to be maintained somehow. The larger the amount of guest RAM to maintain, the larger the maintenance structures and the bigger the maintenance overhead. VirtualBox maps all memory of the guest into the VM process. This could be changed but this would induce more overhead and this would require a rewrite of a big part of the VMM. Therefore the limitation for 32-Bit hosts.

comment:22 by Scott Pakin, 15 years ago

I'm confused by your comment, "Therefore the limitation for 32-Bit hosts", in relation to your prior comment, "VirtualBox can now maintain up to 16GB on a 64-bit host." If I have a 64-bit host with significantly more than 16GB of RAM, then can't VirtualBox let me create a guest with whatever my RAM size is minus the size of the VirtualBox maintenance structures? I don't see why there needs to be an arbitrary limit on guest memory capacity.

comment:23 by Frank Mehnert, 15 years ago

Sorry for the confusion, I told you the reason for the 64-bit limit with the first two sentences of my last comment. Only the lines starting with VirtualBox maps all ... were the reason for the 32-bit limit.

comment:24 by sseidel, 12 years ago

Resolution: fixed
Status: closedreopened

I cannot assign more than 8GB to my Linux guest on Windows Server 2008 R2. This is a host with 24GB RAM, 64bit, VirtualBox 4.1.20. Has the guest memory limit been reduced in the more recent versions?

comment:25 by Frank Mehnert, 12 years ago

Description: modified (diff)

What do you mean be 'cannot assign more than 8GB' -- what happens if you try to? Does the GUI not allow you to assign more than 8GB or do you experience a Guru Meditation when the guest starts? The latter is another bug which is reported elsewhere.

Note: See TracTickets for help on using tickets.

© 2023 Oracle
ContactPrivacy policyTerms of Use