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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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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14 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 ...
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1answer
12 views

enable vnc after virt-install

I've created a virtual machine using virt-install with graphics --none. I want to enable vnc. I've tried virsh -c qemu:///system qemu-monitor-command vm171-SC-1 --hmp change vnc :3 but it doesn't ...
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1answer
80 views

Qemu+libvirt+kvm significant performance lag in VM's

I am troubleshooting poor performance on our new VM host machine which is a Dell PowerEdge R415 with hardware RAID. We've got about 20 VM's running like this: qemu-system-x86_64 \ -enable-kvm \ ...
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1answer
56 views

Unable to import Ubuntu virtual machine on Centos 7 kvm host

[root@kvm ~]# virsh create /root/ns1.jesse64.xml error: Failed to create domain from /root/ns1.jesse64.xml error: internal error: process exited while connecting to monitor: qemu-kvm: -machine ...
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libvirt hook qemu suse12

we have this qemu hook. In suse 11 was working well but in suse 12 it is not working. The hook is setting the ports in openvswitch native-untagged. Do you know if there is some libvirt missing ...
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1answer
44 views

Convert virtual disk image to physical disk?

I'm trying to use QEmu for Windows to convert a virtual disk image to a physical SSD. But I'm not sure about the syntax for the output_filename parameter. Here's what I tried: qemu-img convert -p ...
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94 views

qemu-img VHD to raw image convert results in bad geometry:

Is anyone else able to reproduce this? Using StarWind V2V Image Converter on Windows, I'm able to get a valid disk.img file, so the source image.vhd is clean (pulled down from rackspace). Is this a ...
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54 views

OpenNebula glusterfs cannot create on volume

I try to create a VM on my gluster volume, it fails with the following message: Wed May 20 20:37:30 2015 [Z0][DiM][I]: New VM state is ACTIVE. Wed May 20 20:37:30 2015 [Z0][LCM][I]: New VM state is ...
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1answer
53 views

How much of a performance does using QEMU virtualization incur on Windows?

How much of a performance does using QEMU virtualization incur on a Windows host, when both the host and vm are running the same CPU? Older articles indicate that using kqemu avoided the slow down in ...
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1answer
121 views

Enabling Qemu/KVM Filesystem Passthrough Centos 7

I have a system running Centos 7 with the stock qemu/KVM code. I have several virtual servers running on this system and would like to enable the filesystem passthrough option. So far, I have not ...
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44 views

Why are Windows XP and 7 qemu/kvm guests not recognizing updates to a local Samba share?

I develop cross-platform software and test the Windows ports with wine, Windows XP, and Windows 7, the latter two tested using qemu with KVM. I also have several versions of OS X and Debian Wheezy as ...
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107 views

qemu-img snapshot on live VM

I have created multiple KVM VMs using QCOW2 images. Each VM has its own qcow2 file and is not based on any backing file. My question is specifically related to snapshots of QCow2 images on these ...
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2answers
29 views

I added space to a kvm img file but the physical extents do not show up in lvm

I ran qemu-img resize kick.img +12G and thought I'd see some free physical extents when running pvdisplay but nope. When I run virt-filesystems --long --parts --blkdevs -h -a kick.img I see the space ...
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1answer
84 views

CentOS Qemu+KVM lot of virtual machine processes

I am on host-machine with Centos 6.5, qemu+KVM and 2 virtual hosts in it (behind NAT). Both virtual hosts were configured with Virtual Machine Manager (one of them is with Windows 2003 and other with ...
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1answer
34 views

libvirt management is slow under ubuntu

I've just done a fresh install of KVM/Qemu under Ubuntu 14.04.2 on an older (C2D gen) server with dual quad core xeons and 24 gb of ram. I'm finding that I'm waiting for operations in virsh for around ...
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80 views

KVM GPU passthrough working only with cirruslogic vga added, VM goes in paused state if remove cirruslogic and boot with passed-through gpu only

It seems I had this working once but maybe that was when my kernel wasn't trying to load the fglrx kernel module. (I think before it was loading 'radeon' module) Not sure if this was the issue/change ...
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19 views

What is the maximum number of VM which can be used for a single baseimage? [duplicate]

In my current project I am using KVM hypervisor and qcow2 as a base image. On that base image I am creating many VMs, say 100s of VMs. So, my question is that will that baseimage be a bottleneck for ...
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1answer
1k views

Which is better image format, raw or qcow2, to use as a baseimage for other VMs?

I am using a baseimage and based on that creating many VMs. And now I want to know which is better, qcow2 or raw to use for a baseimage. Moreover, can you please tell me if there is any advantage of ...
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1answer
64 views

Revert libvirt external snapshot

Having some issues understanding how to revert snapshots on ubuntu 14.04 using KVM... Until now i have been using internal snapshots, however due to space issues (space not being re-allocated after ...
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2answers
430 views

Extremely slow qemu storage performance with qcow2 images

I'm running some images using libvrit on a small Openstack cluster. Storage performance on these machines is extremely poor: my monitoring tool shows 100% utilisation (usually on writes but sometimes ...
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220 views

Backup KVM running machine safely

I read some solutions to make backups of running VMs, but all take offline snapshots that seems difficult that will work if the VM has high I/O load. I have tested but i have doubts about the process ...
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1answer
154 views

Qemu Proxmox VM - Network access to guests for BackupPC backups

Environment I rent a dedicated server from OVH and installed Proxmox 3.3 (which is based on Debian 6 Wheezy) in order to create and manage multiple Virtual Machines on it. Each VM is configured to ...
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1answer
182 views

How to configure and use qemu-guest-agent in Ubuntu 12.04? My main aim is to get the IP address of guest VM from Host machine

In the documentation it is not very clear that how to install and use qemu-guest-agent in Ubuntu 12.04. So can anyone help me out ? http://wiki.libvirt.org/page/Qemu_guest_agent It is a daemon ...
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2answers
106 views

How to measure boot time of a VM from host machine?

On both Guest machine and host machine, I am using Ubuntu 12.04. As a hypervisor I am using KVM. I want to perform some experiments related to boot-storm and I have created all other scripts to ...
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3answers
356 views

attaching usb dongle to KVM VM

I'm struggling to connect a usb device, that gets detected correctly by the host, to a kvm vm. I have a freshly installed Ubuntu Server 14.10 as KVM/QEMU host. I set up an Ubuntu vm using this ...
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123 views

QEMU/KVM port forwarding issues

I'm trying to access websites hosted on a QEMU/KVM debian virtual machine from a Ubuntu host machine and other PCs/devices on the host machine's network. Later, I'd like to access this from the ...
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1answer
243 views

Extremely slow disk IO in qemu-kvm VM

I have a VM running Debian Woody (kernel 2.4.18). Qemu-2.1.2, 2 CPU cores, 512M RAM, qcow2 image connected as IDE, ext3. The issue is that disk IO is slow. Here is a result of dd "benchmark" right ...
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125 views

Force libvirt to pass always the same device number to the guest on USB device reconnection

I have a HP plotter connected with a USB cable to a debian server through a USB hub. On the server there is a virtualized Windows XP. Everytime I reboot the plotter a different device number is ...
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85 views

gluster libgfapi HA

I was exploring KVM_qemu with gluster distributed storage. My goal was to build a test cluster with complete HA . i.e HA for VMs as well as gluster storage . I'm planning to setup a 3 node gluster ...
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1answer
130 views

Changing qemu/libvirt default gateway IPv4 IP to something other than x.x.x.1/24

General info: I have a KVM-libvirt/qemu running on ArchLinux; 3.18.2-2-ARCH ls | egrep -i 'libvirt|qemu' libvirt-1.2.11-1-x86_64.pkg.tar.xz libvirt-glib-0.2.0-1-x86_64.pkg.tar.xz ...
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40 views

QEMU stop/continue memory releasing

When using qemu-monitor console, i do PAUSE / CONTINUE of different VMs with stop/cont commands, which works ok, and my main CPU usage stays low. Is it possible to keep memory usage low this or ...
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23 views

mounting logical volume attached to vm while vm is running

i am experimenting lvm2 and qemu-kvm. and I want to share and ask some questions. at the end of there is appendix what i am doing. a logical volume on host is attached on guest host (vm) as vda. this ...
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295 views

virt-install fully automated install

I'm looking into ways of installing/deploying a VM completely automated (no user interaction). So far I have tried QEMU and virt-install along with QEMU. The issue with qemu is that injecting ...
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1answer
100 views

Qcow2 images growing far beyond what they should

I am using ubuntu 12.04 and have seen this: https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/1025244 Our qcow2 images are growing far beyond what they should... with some of them growing to as ...
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88 views

Why ssh tunnel cannot create in the virtualbox or qemu with force mode (-f)?

I try on the dedicated server root@debian:~# strace -e open -f sshpass -p guest ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null guest@198.51.100.11 -C -N -D 127.0.0.1:22220 -f [pid ...
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1answer
193 views

qemu, kvm: Guest: No DHCPOFFERS received

I'm trying to set up a virtual machine (guest) wich should act as router (ubntu 14.04). The host is a CentOS 7 machine (4x LAN). The guest should get a public ip address over it's eth0 (guest), wich ...
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1answer
408 views

Linux QEMU issue with bridge network interface

I am trying to setup a bridge interface for one of my QEMU running on CentOS 7. I have below scripts for TAP interface running $ cat /etc/qemu-ifup ifconfig ens192 down ifconfig ens192 0.0.0.0 ...
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319 views

KVM does not boot with .iso disk images. Device or resource busy?

I've been trying to set up a windows VM on my Ubuntu box by following the linked blog post http://www.pugetsystems.com/labs/articles/Multiheaded-NVIDIA-Gaming-using-Ubuntu-14-04-KVM-585/ So I have ...
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1answer
141 views

why linux bridge shows 2 mac addresses for one qemu vm?

I am new to qemu networking and pretty confused about the following situation. I launched 5 VMs. Each connects to br0 through a tap device. I also have a dnsmasq listening on br0 for DHCP. The ...
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156 views

Guest-VM can only ping CentOS KVM host, cannot access anything else

[root@KVMHOST]# ifconfig br0 Link encap:Ethernet HWaddr 00:1E:67:6B:17:2F inet addr:200.200.100.54 Bcast:220.225.255.255 Mask:255.255.0.0 inet6 addr: fe80::21e:67ff:fe6b:172f/64 ...
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3answers
2k views

How can I change Qemu KVM machine architecture from 440fx to q35 with virsh edit or virt-manager

Still trying to get GPU passthrough working and decided to change machine type from older 440fx to q35 ie pc-q35 but if I do virsh edit on the config it refuse to save saying "PCI Bridges not ...
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1answer
1k views

Debian Jessie Qemu KVM GPU Passthrough to Windows Virtual Machine guest Virt-Manager error Bus PCI not found

I'm having problems with Virt-Manager not wanting to boot a VM and giving error: Error starting domain: internal error: process exited while connecting to monitor: char device redirected to ...
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181 views

libvirt / kvm guests take very long time to start after host reboot

Host system is CentOS 6.5 x86_64. I have setup an Ubuntu guest by following this wiki. The guest works, but: if I reboot the host, it takes a very long time (about 30 minutes on the last reboot) ...
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2k views

Convert VHD to use on QEMU KVM

I try to convert a .vhd file (VPC) and get this error. I tried different .vhd files without success. I tried also with a fresh exported VHD with disk2vhd and backup Hyper-V .vhd. qemu-img convert -f ...
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155 views

Enable SDL for KVM under CentOS 7

I'm trying to set up a VM in CentOS 7 with an SDL display, but every time I try to run it, I get the following error: Error starting domain: internal error: process exited while connecting to ...
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1answer
73 views

Connect to the text console of a running VM

I have a running VM with vnc disabled. This is the command running it: qemu-system-x86_64 -enable-kvm -name scratch -S -machine pc-i440fx-trusty,accel=kvm,usb=off -m 512 -realtime mlock=off -smp ...
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1answer
175 views

qmp-shell doesn’t recognize commands

So, there is a python script that allows to connect to QEMU monitor from a usual shell. I had to download a bunch of files from the QEMU source tree, and add -qmp unix:./qmp-sock,server,nowait to the ...
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2answers
244 views

unable to start the installation of a kvm win7 guest

I am using this command (using virt-install on a debian 7 host) to start the installation of windows7 guest OS. I have assembled the following from a plethora of sites virt-install --connect ...
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2answers
898 views

Guest networking not working on Debian Jessie Host server KVM with br0 bridged network

GUESTS networking not working at all. In other words guest can not ping host or lan gateway. I have br0 bridge already created, also brctl show that vnet0 was properly added by KVM to br0 on guest ...