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/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
249 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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32 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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1answer
45 views

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 ...
3
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1answer
85 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
158 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> <memory>...
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151 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
159 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
161 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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2answers
59 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 ...
3
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1answer
52 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
116 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
52 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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118 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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0answers
25 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
535 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
281 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
34 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
933 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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0answers
91 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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0answers
21 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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121 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
98 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
272 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
773 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 ...
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1answer
3k 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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184 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
121 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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0answers
116 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 ...
6
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1answer
70 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 ...
3
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1answer
90 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
142 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 $MODEL,+...
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1answer
794 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 -...
3
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0answers
573 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
483 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
72 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 ...
3
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2answers
695 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
1k 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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0answers
121 views

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 ...
0
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1answer
215 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 "D:\...
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0answers
333 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 ...
2
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1answer
501 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
2k 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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0answers
198 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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1answer
2k 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
39 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
316 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 ...
0
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1answer
76 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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2answers
19k 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
412 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 ...