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Questions tagged [virtual-machines]

A virtual machine (VM) is a completely isolated guest operating system installation within a normal host operating system. It is a software implementation of a machine (i.e. a computer) that executes programs like a physical machine.

30
votes
12answers
73k views

Is it possible to setup a virtual machine inside another virtual machine

I have been playing with virtual machines latley, and wondered if I could run a virtual machine inside a virtual machine? Is it possible? Is it practical?
54
votes
14answers
216k views

How do I know if I'm working on a Virtual Machine or not?

Is there a way to know if the Windows machine I'm working on is virtual or physical? (I'm connecting with RDP to the machine. If it's a virtual machine it is working and handled by VMWare).
59
votes
9answers
157k views

Creating a virtual machine in VirtualBox from a physical one

Is there any way to create a virtual machine that you can use in VirtualBox from a physical installation that you have? For instance, if I have Windows XP installed on a physical computer and want to ...
21
votes
10answers
32k views

Sync LVM snapshots to backup server

I have a number of Xen virtual machines running on a number of Linux servers. These VMs store their disk images in Linux LVM volumes with device names along the lines of /dev/xenVG/SERVER001OS and so ...
6
votes
4answers
6k views

Is it necessary to have RAID in a virtual machine?

I have a Windows 2008 Enterprise on RAID 10 running Active Directory, Hosted Exchange, and a web server on HyperV VMs. Do I need a virtual RAID for Exchange? If so, why? Edit: thanks everyone for the ...
81
votes
6answers
83k views

What range of MAC addresses can I safely use for my virtual machines?

I want to assign my virtual machines MAC addresses so that I can configure DHCP reservations for them so that they always get the same IP address regardless of which host hypervisor they are running ...
73
votes
2answers
109k views

Is it possible to make Nginx listen to different ports?

I created one Nginx with one Linux Azure VM, is it possible to make nginx listen to different ports so that when I change the port number, the content would be different. I found there would be a ...
27
votes
4answers
34k views

Why VM snapshots are affecting performance?

I read in one of the VMware KB articles that snapshots will directly affect VM performance. But my team keeps asking me how snapshots can affect performance. I would like to give them solid reason ...
5
votes
1answer
2k views

How can I stop Azure from randomly replacing network cards on VMs?

Azure seems to have the habit of randomly changing the hardware configuration of virtual machines, without telling anything to the user. This is of course mentioned in the documentation, although ...
15
votes
2answers
340 views

How to get free space from mounted drive Redhat 7

In our VM infrastructure, we have clustered hosts going to a SAN. What i am trying to figure out is how much "white space" is left over when deleting files within our Redhat servers. On our Windows ...
2
votes
3answers
2k views

running Samba Active Directory Server on Windows desktop (for developing)

Huh, I completely confused by others editing my post... breaking all system of referencing and linking into a mess... Bifurcating the question (1) Can anybody share experience and/or links on ...
1
vote
2answers
7k views

Server 2008 DC rejecting replication requests

Have a DC that has recently been part of a business continuity test. From what I understand the server (which is virtual) was snapshotted, test carried out while the link between the two sites was ...
79
votes
2answers
26k views

Why do we use a OS Base Image with Docker if containers have no Guest OS?

I've just started to study Docker and there's something that's being quite confusing for me. As I've read on Docker's website a container is different from a virtual machine. As I understood a ...
23
votes
17answers
3k views

Virtualization Pitfalls/Lessons Learned

What are some pitfalls or lessons learned after converting existing hardware to a virtualized environment? Is there anything you tried to virtualize but will never do again?
13
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5answers
2k views

Renting a dedicated, but getting a VPS. How to detect? [duplicate]

When renting a dedicated server, how can one be certain than he/she is not getting a VPS or some other virtual machine variant instead of a true dedicated hardware box? Which checks can be run (...
4
votes
2answers
16k views

What is the correct network configuration for a devStack VM (virtualbox)?

Usually when I setup a new Ubuntu VM, i keep the eth0 in NAT mode to get the internet & I add a eth1 interface in HostOnly mode so that I can ssh. But using this devStack guide : Running a Cloud ...
26
votes
4answers
808 views

Will virtualizing a server mean another OS layer to patch and update, more work and greater risk?

I've done a search and have not found anything addressing issues regarding patching and system updates. I've got guidelines that say servers need to have necessary patches. If I have a VM host then ...
17
votes
2answers
4k views

understanding relationship between Qemu and KVM

What is the difference between KVM and Qemu? As I understand, latter is able to provide "user mode emulation" which means that one can run a single executable built for some other architecture like ...
5
votes
1answer
26k views

How to change a VM from split across multiple .vmdk files to a single one or two?

I have a VM with 3 partitions. One main one, one for swap space, one for storage. However, there are dozens of .vmdk files. Some of those .vmdk files are very large (over 1 GB), but the majority ...
2
votes
1answer
1k views

How to make this multiplayer flash game publicly available? [closed]

I have made a ActionScript 3.0 Flash game and implemented multiplayer functionality using SmartFoxServer. Now I want to put this game on my website which is hosted on 000webhost. My game works ...
12
votes
11answers
10k views

Any way to run Linux as a Virtual Machine on top of Windows so can have best of both worlds?

Since Linux has a lot of useful tools, while Windows has a lot of apps (like Chrome), instead of buying another machine to run Linux, is there a way to run it as a Virtual Machine on the PC? The ...
6
votes
1answer
12k views

Ubuntu: Network driver reset to eth0?

I've been trying to get my Ubuntu Server VM running through VirtualBox. I ended up trying several network interfaces because of some networking issues and finally got it working. However, I noticed ...
4
votes
4answers
7k views

Securing a guest VM to give it internet access, but block access to host LAN

I have a Linux guest VM running under a Windows host. If I set the networking mode to NAT, the guest can get internet access (which I want), but can also access the hosts LAN (which I dont). For ...
4
votes
4answers
6k views

Which RAID Level Should We Run For Virtual Machine Storage

We just ordered a server which we are going to use as storage for our virtual machine environment. Basically it will work as a block level storage device running iSCSI to each hypervisor. The server ...
2
votes
3answers
2k views

How to run OS X (Leopard or Tiger) in Windows?

Is there a way to run Mac OS X (Leopard or Tiger) in Windows on a virtual machine? I have 2 GB of RAM and a 2 GHz processor. My processor is an 32-bit AMD, but I don't think this will matter because ...
12
votes
6answers
35k views

Can I run 64-bit VM guests on a 32-bit host?

Can I run 64-bit VM guests on a 32-bit host? If I have a physical PC with 32 bit can I launch a VM that is 64 bit? What virtual machine software (Virtual PC or VirtualBox or other) would allow this? ...
9
votes
4answers
42k views

How to decrease the size of a KVM virtual machine disk image?

How do you decrease or shrink the size of a KVM virtual machine disk? I allocated a virtual disk of 500GB (stored at /var/lib/libvirt/images/vm1.img), and I'm finding that overkill, so now I'd like ...
6
votes
1answer
214 views

How can I increase the throughput/bandwith of my virtual network?

I have some virtual machines servers with some micro-services and do some load tests with JMeter. All the servers including the JMeter machine are sharing the same virtual network. The virtual network ...
5
votes
5answers
23k views

How do I boot a virtual machine image from my network?

I have many machines which require the same configurations. My goal is to boot them all from the network and load a virtual machine. It would be wonderful to have one image for all of our customer ...
4
votes
1answer
8k views

High CPU% stolen on EC2 instance at extremely regular intervals

I have a m1.small EC2 instance on AWS running some websites. I noticed my CPU usage have peaks at regular interval of times, exactly every 30 minutes (0:06, 0:36, 1:06, ...). I've checked my crons (I ...
1
vote
2answers
195 views

Using rsync and which directories should I place in my exclude file when using rsync?

I would like to use a CentOS VM for a mirrored full backup of my CentOS mail server. Both are the same version and are up-to-date. I have found that without excluding certain directories the VM backup ...
4
votes
6answers
815 views

Deploying virtual machines - Windows Guest/Linux Host or vice versa?

I'm looking to deploy several virtual machines for users. They need access to both Windows and Linux. They also need to use the computers graphics card (for Photoshop, modeling, etc) under Windows. ...
4
votes
3answers
2k views

How can I keep important VMs in memory without disabling swap?

VM Host -> Xenon E5-2440 w/ 48G mem... Everything runs CentOS6.5 (2.6.32-431) I have 4 guest VMs running each w/ 2G of memory. Their disk images are local files. The host machine is also running a ...
3
votes
6answers
7k views

How to improve Hyper-V performance

I have a windows 2008 (RC2) server running Hyper-V with all of my company's virtual machines. Most of the machines are used to run Continues integration and test environment. Although each machine ...
3
votes
1answer
4k views

Why are eth0 and vmbr0 (bridge) having the same MAC addresses?

I configured my Debian (with KVM on board) as following: /etc/network/interfaces: auto lo iface lo inet loopback auto eth0 iface eth0 inet manual auto vmbr0 iface vmbr0 inet static address 176....
3
votes
4answers
4k views

How to distribute a virtual machine to allow users to try out a dependency-heavy program?

I have written a piece of academic software that has many third-party software dependencies (and requires a RDBMS). I would like to create set up a Linux virtual machine image preloaded with all the ...
2
votes
3answers
2k views

Virtual Machines List from PowerShell vs PowerShell ISE and PowerGUI

I am confused to why I have different information based on where I try to retrieve it from. I have 3 Windows 2012 servers (G0, G1, and G2) running Hyper-V. The following situation is captured from one ...
2
votes
1answer
5k views

How to stop time synchronization on an Azure VM

I'm trying to simulate a different date/time on an Azure VM but the time keeps resetting itself to the current date/time. Is there a way to force the server to stay at a specific date/time until I ...
2
votes
6answers
2k views

Will the OS crash if the system partition can't be access for a short period?

An operating system is installed in a virtual machine environment, such as VMWare or KVM. A network shared disk volume (e.g., iSCSI disk) is used as the OS system partition. Heavy traffic is running ...
1
vote
1answer
10k views

Why does ProFTPd stop at Entering Passive Mode on Debian on a Windows Virtualbox? [closed]

I have installed Debian Squeeze on a Windows computer with Oracle Virtualbox. Then I've port forwarded port 21 on the NAT adapter. In Debian I've run: apt-get install proftpd Then I uncommented the ...
1
vote
0answers
1k views

Nginx Seems to be Sending Cached Versions of Pages

I have installed nginx, and things work very well for production, but I sometimes have this problem when developing. To reproduce the problem, I have done the following: Create a file in a public ...
1
vote
3answers
2k views

Can a virtual PC find out the identity of its host?

There's a Microsoft Virtual PC instance on my network that runs build scripts and reports problems by sending me an e-mail. I don't what machine it's running on! I can access the machine by Remote ...
0
votes
2answers
9k views

How to get internet access in a Windows 7 virtual machine [closed]

I am running Windows 7 Ultimate and have now set up two virtual machines in Virtual PC. One is the XP Mode machine which runs XP (obviously). When I set it's network connection to Shared Networking (...
18
votes
5answers
1k views

Is there a way to have a virtual machine only have one core yet use three cores on the host machine? [duplicate]

Possible Duplicate: Can a single Virtual Core on a VM use more then 1 physical core? I'm a co-owner of a Minecraft server that is getting rather large each day, but as we get bigger we're running ...
7
votes
4answers
12k views

Virtual Machine guest optimization tips

I've installed Windows7 in VirtualBox 2.2.4 and worked like a charm. But compared with my WindowsXP virtual machine, the performance is slow. I've installed Windows7 in (non-virtual) machines and the ...
6
votes
4answers
10k views

How to enable multiple virtual consoles on linux?

I'm new to linux so I have no clue how to do this (couldn't find it on the web). I'm running a LAMP Virtual Machine and when I press ALT-F2, F3 etc.. to use a Virtual Console I get a blank screen (all ...
6
votes
1answer
10k views

Hyper-V and AD --> recommendations for small site? [closed]

I have a dilemma about how to proceed with new AD / Hyper-V installation and would appreciate your views, experience and advice. Situation: we are a small company with single site (25 users) and few ...
5
votes
4answers
12k views

Disable Time Synchronization on Ubuntu

I am setting up a development environment with Ubuntu in a virtual machine. The date in the VM must be in 2009 due to some silly timebombing issues, so I want to disable any automatic time ...
5
votes
3answers
17k views

kernel warning in logs: set_rtc_mmss can't update from 0 to 58

I've been seeing a bunch of these log messages Jan 3 00: 58: 57 foo kernel: set_rtc_mmss: can't update from 0 to 58 They occur on CentOS 6.4 VMs running on VMware. I understand it's something to do ...
4
votes
1answer
1k views

Potential VMWare 5.1 Fault Tolerance bug/issue?

Background / Setup I've got a fresh install of vCenter Server 5.1 and associated components. I've taken all steps (as far as I can tell) to enable FT, and it worked the first time (yanked a power ...