Browsing articles tagged with "kvmvirtualization - Admins Goodies"
Jul 8, 2013
tom

VM running perfectly when its disk image is deleted?

Does anyone has such experience that you accidentally delete the used disk image when virtual machine is running? I would expect that the virtual machine will fail immediate, but, surprisingly, it still running perfectly. I have tried to execute many I/O commands and even create very large files by “dd” which are totally more larger then the vm’s memory size. But it is still live. Can anyone explain why? Server info: ubuntu 12.04 with KVM […]

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Jun 7, 2013
tom

How do you increase a KVM guest’s disk space?

I setup an Ubuntu guest on a CentOS KVM host with initially 6GB of disk space. How do I go about increasing the Ubuntu guest’s disk space from the command line? EDIT #1: I’m using a disk image file (qemu). Asked by slm stop the VM run qemu-img resize vmdisk.img +10G to increase image size by 10Gb start the VM, resize the partitions and LVM structure within it normally Answered by dyasny Check more discussion […]

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Jan 17, 2013
tom

KVM control guest from host

Virtualbox has a nice feature called Guest control which through guest additions allows the host to execute commands inside a running guest. This can be useful in many ways such as automating deployment of software in the guest. Is there a way in KVM to execute commands in a running guest from the host system. I’m just interested in Linux hosts and guests. Asked by Marwan Alsabbagh No, kvm doesn’t provide anything like that. But […]

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Jan 8, 2013
tom

DRBD & KVM replication is possible?

i have two KVM servers with some virtual machines. Server (A) KVM with qcow2 images Server (B) KVM mount NFS for partiton (with qcow2 images present on server A). My question is simple, what is the best solution for creating virtual disk copies on server B (with virtual machines running obviously). DRBD is one solution?? Asked by Giovanni Bennelli If you just want to replicate the server A qcow2 images on the server B, but […]

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Jan 4, 2013
tom

KVM – Guest does not recognize second NIC

I have a server running Proxmox (a virtualization platform), and created a KVM virtual machine with Ubuntu Server 12.10. After configuring the network, everything works fine, but if I add a second network adapter to that virtual machine, it is not recognized. dmesg | grep -i eth just shows one interface (eth0). EDIT: root@ubuntuserver1:~# lspci 00:00.0 Host bridge: Intel Corporation 440FX – 82441FX PMC [Natoma] (rev 02) 00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA […]

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Dec 25, 2012
tom

KVM/Qemu, Ubuntu: Why do more guests CPUs enhance Disk-I/O rapidly?

We have an Heartbeat/DRBD/Pacemaker/KVM/Qemu/libvirt cluster consisting of two nodes. Each node runs Ubuntu 12.04 64 Bit with the following packages/versions: Kernel 3.2.0-32-generic #51-Ubuntu SMP DRBD 8.3.11 qemu-kvm 1.0+noroms-0ubuntu14.3 libvirt 0.9.13 pacemaker 1.1.7 heartbeat 3.0.5 The virtual guests are running Ubuntu 10.04 64 Bit and Ubuntu 12.04 64 Bit. We use a libvirt feature to pass the capabilities of the host CPUs to the virtual guests in order to achieve best CPU performance. Now here is […]

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Dec 13, 2012
tom

Where are the acpiphp and pci_hotplug kernel modules for KVM hotplug in CentOS/RHEL?

On the this how-to I read the following: I loaded the following modules to get pci hotplug working: acpiphp pci_hotplug You can either add these to your distro’s module list to load on boot, or run a command like this. for m in acpiphp pci_hotplug; do sudo modprobe ${m}; done However, on CentOS 6.3 and Red Hat Enterprise Linux 6.3 this modules does not exist, on Ubuntu Server and Debian 6 it does. Why? Any […]

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Nov 11, 2012
tom

Proxmox VE Logical Volume in RAW format?

I added a Volume group in Proxmox VE as Storage for KVM VMs. A new Logical Volume will be created for each VM, but in Proxmox VE under The Defined Storage which shows list of created Logical Volumes I see my Logical Volume marked as RAW format. Is this a RAW image or a Logical Volume (LVM)? But my main question, Does this really avoid the overhead of going through the filesystem layer on the […]

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Nov 2, 2012
tom

KVM-admin tools required

I require the KVM-admin tools that are supposed to be on the KVM home page http://www.linux-kvm.org/page/Kvmtools#Download but I am unable to find any refernce for then. Can anybody from the forum tell me from where I can get them. If somebody has a copy of them them please share a link so that I can get them. I specifically require the below tools: kvm-admin boot domain_name List item kvm-admin status domain_name kvm-admin status all kvm-admin […]

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Oct 22, 2012
tom

How to makesure VM is in Para virtualization mode on XEN?

I am having a server running XEN,with ubuntu 12.04 as Domain 0. Intel VT is turned on by default and i dont want to run any Windows OS as VM. So 1. how can i makesure that all the created VM will be in paravirtualized mode even with VT enabled? I have heard that in Full Virtualization hypervisor needs to work hard for emulating all the underlying hardware,which may reduce performance for too much i/o […]

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