QEMU stands for "Quick EMUlator" and is a processor emulator that relies on dynamic binary translation to achieve a reasonable speed while being easy to port to new host CPU architectures.

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KVM is there a way to map physical memory to host. Like Xen mapping to Dom0

Been looking for an answer to this for a while. I am switching over from Xen virtualisation to KVM, and have been reading about KVM's ability to overcommit memory. I was wondering if anyone can help ...
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Installing VirtIO SCSI on Windows Guest fails

I'm running Windows 10 as guest via KVM / qemu. Unfortunately, Windows doesn't recognize the fedora virtio drivers I want to install for better HDD perfomance. The driver itself does show up, but ...
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25 views

How to create virtual networks by using libvirt?

I have installed qemu/kvm and have tried to create some virtual machines and network them together. What I would like to achieve is 2-3 virtual machines in their own private network (e.g. ...
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15 views

How does Qemu handle memory?

I'm having a real hard time understanding something and I was wondering if anybody has any experience with this and is able to help. I have two KVM VMHosts, one running qemu 2.4.1 and the other ...
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1answer
24 views

Correct virtio setup on Ubuntu 14.04 64-bit host

At the present moment, my guest is running inside qemu and host is kvm intel, running Ubuntu 14.04, kernel is 4.3.0 stable. From within the guest, when I run "hdparm -i /dev/sdb" on the guest, I ...
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47 views

Ubuntu + bridge +qemu + tap + virtio dropping packets

I've got what I think is the standard qemu bridge/ubuntu tap interfaces set up running variety of VMs on my Ubuntu host. All the VMs I'm having trouble with are Windows images. I have researched this ...
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10 views

Bridged qemu machine cannot receive packets, these are dropped [migrated]

I've created virtual machine (ppc) with bridged interface (using bridge helper) on archlinux. Machine can send packet out, but cannot receive anything. I can see packets (dhcp discover,request and/or ...
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1answer
16 views

Is a QEMU installation on a raw disk backward compatible?

I create a qemu image like this: qemu-img create -f raw my_disk.raw 2G and (manually) install debian into it: qemu-system-i386 my_disk.raw -enable-kvm -m 1024 -cdrom my_debian_cd.iso Say I do ...
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42 views

FreeBSD 10 guest on qemu/kvm CentOS 7 host

I'm trying to install FreeBSD 10 on CentOS host without using graphics (using only serial console). I've tried: # virt-install -n freebsd-a -r 512 --vcpus=1 --os-variant=freebsd10.0 --graphics none ...
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2answers
149 views

KVM top shows high CPU load on host for windows7 guest though windows is on idle

we have an virtualization environment with actually 4 VMs (2 x linux, 1 x w2k3, 1 x win7). In the host system (Debian Jessie) top always shows a CPU load of 30-70% (or more) for the qemu process of ...
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2answers
64 views

KVM: Need multiple Virtual Machines to share a VLAN'ed interface

I'm not sure how to configure my Linux server which has a single VLAN'ed interface to support a number of Virtual machines which I want to bridge to my network (so that all their services appear to ...
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66 views

Proxmox/KVM: Can not clone VM

I would like to create a clone of a KVM machine - yesterday I was able to create a clone of the same machine within some minutes. Now it takes hours and is still stuck an "0%": create full clone of ...
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1answer
18 views

Files left over after removing KVM guest

Looking at this post I ran the following commands to remove a VM: sudo rm /var/lib/libvirt/images/centos01.qcow2 sudo virsh undefine centos01 --managed-save --snapshots-metadata But it looks like I ...
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1answer
235 views

WARNING KVM acceleration not available, using 'qemu'

Running debian (Linux Rick 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u6 (2015-11-09) x86_64 GNU/Linux) Looking at my cpuinfo I can see I have vmx support: flags: fpu vme de pse tsc msr pae mce ...
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1answer
26 views

QEMU/KVM nic properties

1) What's the use of the addr value when specifying a new network interface on QEMU/KVM ? Example: qemu -hda deb.img -net nic,addr=192.168.1.10 2) Is there a way to specify directly the IP address ...
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1answer
128 views

KVM Virtual Machine: Wrong Disk Size

Ever since I did yum update and tried to create a new (for example) 10GB Disk KVM VPS, the reported disk space inside VM is locked to the initial template size (usually 1GB for linux template). ...
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26 views

Qemu - Reduce virtual disk size

I have a problem trying to reduce a virtual machine's disk. The host is CentOS 6.5 and the guest is Windows XP. The size of the virtual drive is 250GB, but I want it smaller. How can I do that? ...
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vlan qemu: guest listening from other guests

I'm trying to simulate a little network of 3 machines using QEMU where a machine (deb1) is directly connected with the host and the other 2 machines (deb2, deb3): Host ...
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1answer
43 views

kvm snapshot-create-as failed

I have Ubuntu server with qemu/kvm. I'm try to create snapshot (for further backup) using libvirt and get this error: # virsh snapshot-create-as --domain 56 --name copy_snap --no-metadata --disk-only ...
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1answer
26 views

Libvirt guest destroyed after shutdown

I have created a VM withLibvirt and when I shut it down whether forcefully or with ACPI, it gets deleted. I create it: <domain type='kvm'> <name>deneme2</name> ...
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51 views

Soft Lockup - CPU Stuck qemu-system-x86

I have a system running: * openstack icehouse * Linux 3.13.0-48-generic #80-Ubuntu SMP Thu Mar 12 11:16:15 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux(Ubuntu 3.13.0-48.80-generic 3.13.11-ckt16) Suddenly ...
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1answer
59 views

low write disk speed of windows kvm guest with LVM

I have a trouble with my windows 2008 R2 KVM guest. It write speed to disk extremely slow: But on another VM (windows 10) on this KVM host write speed is ok: # cat /etc/system-release CentOS Linux ...
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1answer
42 views

How to explain the machine type concept in the virtualization?

When I was under Debian Wheezy, virt-manager created virtual machines with the "pc-0.12" machine type. Since I am under Debian Jessie, virt-manager creates virtual machines with "pc-i440fx-2.1" ...
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24 views

Running two Ubuntu KVM virtual machines with bridged (tapped?) networking

I have a server that's running Ubuntu 14.04, and I'm trying to run two virtual machines with bridged networking at the same time. The networking of the first VM works, but the second one has no ...
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1answer
37 views

KVM port binding

I followed this tutorial to install a KVM virtual machine on my ubuntu server. Now i need to bind a port from the guest to the host. I tried several tutorial to bind the port, but nothing worked. My ...
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1answer
41 views

Options for optimising QEMU emulation (-cpu flag)

I have been doing some reading about optimising QEMU and one thing that I am confused about is the -cpu switch. At the moment I am using -cpu host which is supposed to transfer all the hosts cpu ...
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1answer
32 views

Golden image updates in qemu

Consider that there are 100 windows virtual machines coming from a single base image and each vm is added to domain along with minor other machine specific settings which can be done by a script. ...
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57 views

Qemu Virtual machine very slow

This is my first time using Qemu, and creating my own virtual machine. I feel like a complete newb ;( Debian Linux host Uname -a: Linux 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u5 (2015-10-09) ...
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22 views

Remove Hardware Support From Qemu [closed]

I am currently experimenting with Qemu 2.4.1 and I'd like the support for few hardware to be removed. Say like USB/Mouse/SoundCard etc. While I was tinkering with the source code, I was able to ...
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4answers
158 views

How to “really” reduce the size of KVM VMs images?

I've spent many hours searching the web about how to shrink KVM virtual disk images, especially for Windows guests, with no luck. All I've found is to zeroize the VM free space, defrag the virtual ...
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1answer
152 views

Live Backup using Proxmox's snapshot-drive command

I have a KVM server(not on a proxmox node), my VPS is based on qcow2 format and I would like to do a live backup of the vms. I have understood there are two types of backup, Internal and External, I ...
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1answer
16 views

Qemu qmp snaphot-drive

what is the correct method to use qemu qmp snapshot-drive ? Is there any other way to create snapshot of qcow2 based VPS without using virsh snapshot-create ? They seem to corrupt the filesystem on ...
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2answers
321 views

Solidworks: activation license mode is not supported in this virtual environment (Qemu-KVM)

The question is not around Solidworks actually, so please continue to read. The whole idea of virtualization is to be hardware independent. Before our eyes a whole new dependency level is being ...
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54 views

How to prevent conntrack overflow on host with many qemu guests

Is there any way to make iptables conntrack use separate data structures for each network interface? Would network namespaces help here (put each guest together with its tap device in its own netns ...
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18 views

KVM - Reassembly of packets done by virtual bridge interfaces

I've 2 guest OSs in KVM based setup, talking to each other using a virtual bridge(VBR) Client--Device1--(VNET1)----VBR----(VNET2)Device2--- Server I see that the packets are getting fragmented by ...
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76 views

Use host's VGA output from virtual machine

Is there a way to stop a host OS from using its VGA port (on the motherboard) and allow a VM to use it instead with KVM-QEMU? I have read about VGA pass-through, but all the discussion I've found on ...
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1answer
52 views

port forwarding with libvirt

I'm trying to get port forwarding working through libvirt on top of QEMU and KVM. I found this article (https://snippets.webaware.com.au/howto/running-qemu-with-port-redirection-through-libvirt/), but ...
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2answers
123 views

How do I connect to my libvirt/qemu/guests ? (with no ip address)

I have inherited the administration of a trusty ubuntu server with several virtual servers, also ubuntu using libvirt and qemu. I have the problem I cannot connect to these virtual servers/guests. ...
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1answer
340 views

Best options for KVM/qemu/libvirt VM migrations without shared storage

My team has recently been tasked with improving the virtualization infrastructure at the company and one thing we're looking into doing is speeding up migrations. We use local storage only on all VM ...
2
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1answer
820 views

Backup of running KVM qcow2 VPS

I want a robust method of taking backup of KVM VPS of qcow2 file, while running. After searching for a long time I found that we can use rsync for live backup. I used following command for rsync: ...
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116 views

Running a virtual machine remotely; connect it to the local network

The scenario is as follows: I have a virtual machine remotely, e.g. on a server somewhere in a data center, and I connect to it from my laptop on a restricted network (only tcp 80 and 443 are open). ...
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1answer
90 views

Installed KVM, but Virtual Machine Manager says localhost(QEMU)

My understanding is that KVM uses the CPU virtualization properties and is much faster than QEMU, which is emulation. I used the Virtual Machine Manager to create the virtual machine. I am nearly ...
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79 views

Set custom cpu string for qemu/kvm

I have some virtual machines with software, which licensing check depends on cpu string. They're running on kvm - with default cpu string value - which is QEMU Virtual CPU version 1.7.1 After ...
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61 views

Prevent hijacking IPs in KVM/libvirt

How can I prevent a VM user/client from accessing IP addresses he doesn't own but are routed over the same bridge on KVM/Libvirt? IP addresses are routed to a cisco switch vLan consisting of a /24 ...
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1answer
66 views

How to make sure qemu-img resize does not lose data?

I'm trying to understand how qemu-img resize shrinks the virtual disk. Let's say qemu-img info shows that the virtual size is 20G, and the disk size is only 1G. Now I want to shrink the disk from 20G ...
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1answer
84 views

virsh adding x2apic, cache specific options to kvm config

Anybody know the syntax how to add +x2apic to the virtual machines xml files when I edit them with "virsh edit vm"? From the command line it would be starting with this flag: qemu -cpu ...
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1answer
319 views

QEMU multiple port forwarding

I would like to forward more than one port. This command run my VM and forwards RDP port successfully: qemu-system-i386 -net nic,model=rtl8139 -net user,hostfwd=tcp::3389-:3389 -m 512M -localtime ...
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261 views

qemu with network namespaces and openvswitch

I want to put each qemu process in its own network namespace. However when I do this I cannot get bridged networking to work. This doesn't use namespaces, but makes qemu work with ovs: ovs-vsctl ...
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334 views

QEMU USB passthrough is not working

I stuck at getting USB passthrough working with Windows 8.1 guest OS on Ubuntu Server 14.04. I started by installing qemu using the Ubuntu Documentation (https://help.ubuntu.com/community/KVM). The ...
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1answer
241 views

kvm/qemu host windows guest BSOD about driver_irql_not_less_or_equal for viostore.sys

I have a KVM/Qemu host running 4 Windows Server 2012 guests and after upgrading the host from Ubuntu 12.04 to 14.04 I get blue screens with a bug check string of "driver_irql_not_less_or_equal" that ...