[Bug 695825] Re: Ubuntu KVM error with guest memory >4gb ram

[Neil Hunt]

Sean,

how can I enable KVM Acceleration? I am actually getting very poor
performance from Ubuntu KVM at the moment. Running on a 24-core server
with 64gb ram, but my guests are running very slowly. Is there
anything I can do to improve this? Also, if I enable this somehow,
does this fix the 4gb ram limit or do I need to apply a patch?

On Mon, Jan 3, 2011 at 11:26 AM, Serge Hallyn <695825 at bugs.launchpad.net> wrote:
> Please note that running with kvm acceleration, you will be able to give
> guests more memory.
>
> --
> You received this bug notification because you are a direct subscriber
> of the bug.
> https://bugs.launchpad.net/bugs/695825
>
> Title:
>  Ubuntu KVM error with guest memory >4gb ram
>
> Status in “qemu-kvm” package in Ubuntu:
>  Won't Fix
>
> Bug description:
>  Binary package hint: qemu-kvm
>
> 1. Ubuntu 10.10 Maverick
> 2. qemu-kvm 12.5
> 3. We are supposed to be able to run guests on a 64-bit Linux at up to 512gb of ram, and I am only trying to run it with 8gb of ram and it is failing.
>
> When I'm trying to launch a VM with more than 4gb RAM, I receive the error message:
>
> Traceback (most recent call last):
>  File "/usr/share/virt-manager/virtManager/engine.py", line 814, in run_domain
>    vm.startup()
>  File "/usr/share/virt-manager/virtManager/domain.py", line 1296, in startup
>    self._backend.create()
>  File "/usr/lib/python2.6/dist-packages/libvirt.py", line 333, in create
>    if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self)
> libvirtError: internal error process exited while connecting to monitor: char device redirected to /dev/pts/5
> qemu: without kvm support at most 4095 MB RAM can be simulated
>
> I have the packages qemu-kvm, libvirt-bin, and virt-manager installed from apt.
>
> I see something about a patch being applied to qemu 12.0 that addresses this exact message, but the Ubuntu package qemu-kvm is 12.5 so it should be fixed?
> http://www.spinics.net/lists/kvm/msg30336.html
>
> To unsubscribe from this bug, go to:
> https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/695825/+subscribe
>

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https://bugs.launchpad.net/bugs/695825

Title:
  Ubuntu KVM error with guest memory >4gb ram