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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How to efficiently share host's folder with KVM guests?

I am configuring the service which stores plenty of files uploaded by nginx in /srv/storage dir on host system. These files are processed by worker KVM guests which may create new files or assign ...
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3answers
1k 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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2answers
25 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
37 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 ...
11
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1answer
4k views

Read/write access for passthrough (9p) filesystems with libvirt/qemu?

I have recently started experimenting with the support for passthrough filesystems in recent versions of KVM/QEMU/libvirt. Making the filesystems available for read access has "just worked", but I'm ...
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1answer
1k views

How to fix a frozen qemu VM?

I have a qemu hypervisor on RHEL 6.4 that hosts VMs that will quite often lose their connection to the network. When the VM has lost its connection I can view and interact with the it using ...
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1answer
1k views

setting CPU cache size and model for KVM guest

Is there any possibility to create a custom CPU model for KVM Linux guests, or at least to modify parameters such as cache size and model name? I know I can set CPU features, topology and pinning and ...
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1answer
14 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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1answer
1k views

Any way to convert qcow2 to ovf?

In our application we are downloading a qcow2 image and after that we are supposed to import that as OVF. So any way to convert qcow2 --> OVF or qcow2 --> vmdk(using qemu-img convert) --> ...
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34 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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1answer
1k views

How to speed up QEMU on Windows host?

We want to run our Ubuntu 64bit web server virtualized/emulated on a Windows 64bit host. Intended use is to distribute the VM to customers who might not have "elevated" or "admin" rights on the ...
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3answers
165 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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2answers
342 views

qemu-kvm fail to boot Centos 5.3 after Kernel update at the host (feodra)

After updating Fedora 18 to kernel 3.9.x (current 3.9.4), I can no longer boot my Centos 5 guest OS. When I try to boot, the process halt at start and the CPU core work at 100%. If I boot Fedroa ...
0
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1answer
92 views

How to start a new instance of QEMU based on the same image and snapshot?

I have a QEMU image (qcow2) with a snapshot stored in it. Right now I'm using libvirt to start it. However, I want to be able to run more than one instance of the same image snapshot. I guess I can ...
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1answer
176 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
34 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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0answers
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 ...
2
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2answers
3k views

How to start qemu directly in the console (*not* in curses or SDL)

I seem to recall being able to start qemu with only the terminal emulator output, with the graphic window disabled. And here I don't mean with the ncurses interface, that one is nice, but I want the ...
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2answers
167 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 ...
2
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2answers
64 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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119 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 ...
1
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1answer
111 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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80 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 ...
0
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1answer
162 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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2answers
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Is there any way to shrink qcow2 image without converting it raw?

Is there any way to shrink qcow2 image without converting it raw? I cannot convert it to raw because I don't have disk space enough for raw image.
0
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1answer
448 views

How to install kvm in Debian (Lenny) over powerpc

I want to install kvm on debian(lenny). I have learnt that packages kvm and qemu-kvm are not available for powerpc architecture. I have found two packages(kvm-source & qemu) and installed it. Now, ...
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0answers
102 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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0answers
89 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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69 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 ...
0
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1answer
85 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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28 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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21 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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205 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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2answers
766 views

Disable TCP checksum offloading on KVM virtual network

I have a virtual network for connecting KVM guests with the host. I need to disable TCP checksum offloading on this network. The ethtool works fine but I want to disable it permanently and I could ...
0
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1answer
165 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 ...
0
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1answer
73 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 ...
2
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1answer
2k views

qemu-system-x86_64w.exe : could not open disk image D:\img.img: Permission denied

I'm trying to use qemu on Windows (8), because I have to emulate an USB mass storage device (VirtualBox still doesn't handle USB3 which my computer only have .. and if I could have qemu working it ...
0
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1answer
1k views

How can I set up a VM of Solaris 11 / Sparc on Windows / x86 host? [closed]

I need to test a custom binary that was originally compiled for an earlier version of Solaris on Solaris 11. Being poor, I don't have a spare SPARC server lying around on which I can install Solaris ...
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73 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
326 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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0answers
274 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
99 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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1answer
379 views

qemu/virt-manager no permisson on shared folder

I have a strange problem. Iam trying to create a shared folder via the add-hardware->filesystem option. For Type and Modus i choose Passtrought and for Driver Path. The Source Path is /free and target ...
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0answers
144 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 ...
0
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3answers
873 views

qemu.img: conversion of a VMDK image failed with error “invalid VMDK image descriptor”

I trying to convert a VMDK image (Windows installed) to RAW format with the qemu-img command. However, it is failing with the following error: $ qemu-img convert -f vmdk -O raw image.vmdk ...
2
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2answers
1k views

Windows guest on KVM/Qemu suffers horrible key lag

Host OS is Arch Linux with the following versions:- qemu 2.1.0-2 libvirt 1.2.7-1 linux 3.15.8-1 Guest OS is Windows 7 64-bit. This problem did not exist when I first created this VM and started ...
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2answers
3k views

does KVM raw images support preallocation?

I was trying to create a raw image with this command: qemu-img create -f raw -o size=200G,preallocation=metadata file.img but seem that it raw images doesn't support preallocation. if so why there ...
1
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1answer
129 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 ...
0
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1answer
810 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 ...
2
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0answers
145 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) ...