compared with physical machine, the VM is much more easy to change the machine scale and spec, do you think using VM(VirtualBox, or VMWare) to run benchmark is reasonable or not?
As long as you're only comparing code executed in a VM to other code executed using the same VM program, OS, and virtual architecture, and don't expect the numbers to compare reasonably with benchmarks obtained while running native code in an actual processor, you shouldn't have any trouble using a VM for benchmarking to simulate weaker machines than your actual PC
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I want to get CPU usage (cumulative) for each VM hosted on a VMware ESXI host.
I tried using Power CLI command 'Get-VMHost' but it only gives the overall CPU usage by ESXI host.
For CPU usage esxtop is a very powerful ESX command and you have to run it at the CLI. I haven't used the Power CLI so I'm unsure if it's available there but it is definitely available at the CLI which VMware tries to discourage you from using (see https://kb.vmware.com/s/article/2004746). Documentation for esxtop for the latest release of vSphere is at https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.monitoring.doc/GUID-D89E8267-C74A-496F-B58E-19672CAB5A53.html.
That document is a bit terse and in terms of getting CPU usage for each VM this old documentation for esxtop may guide you a bit better https://www.vmware.com/pdf/esx2_using_esxtop.pdf. In particular note the different nomenclature of ESXi (and ESX) for which the primary unit of address space and execution is the "world" rather than the "process". Thus you want to get the CPU usage for all "worlds" associated with each VM. Some VMs may have only a single "world" and some may have several and it is configurable. As for esxtop, it has been around forever and most likely it can still today provide the same functionality that it did over a decade ago with ESX 2.
I work with a number of different specialized and configured OS environments but I generally only use one at a time. I have a processor-beefy laptop but storage is always an issue. It would also be good to have a running backup of each environment so I can work from other hardware.
What would be ideal would be if I could run some kind of VM library server that maintained canonical copies of each environment from which I could DL local execution copies to my local machine to work with and then stream changes back to the server image as I did my work.
In my research it seems like a number of the virtual machine providers used to have services like this (Citrix Player, VMWare Mirage) but that they have all been EOLd.
Is there a way to set something like this up today? I'd love a foss solution based on KVM but id be willing to take a free proprietary solution.
If hardware support is a must for virtualization, how can Java Virtual Machines run on machines without support for virtualization ? Or is JVM not a virtual machine ?
A JVM is not virtual in the same sense as a VirtualBox or VMWare virtual machine. It is a 'machine' that implements the Java bytecode, not a virtualized version of actual hardware.
The term-of-art 'virtual machine' was coined a very long time ago for the following scenario:
make up a computer, like Knuth's MIX.
write a computer program that implements the made-up computer.
run programs
When this virtual machine runs, it's a completely ordinary program, running completely in user mode. It needs no special help from the hardware or operating system to work reasonably well. This is especially true of the JVM, since the Java byte code does not deal with low-level hardware I/O or other things which are hard to simulate.
Later, historically, (to pick a particular instance), IBM invented VM/370. VM/370 uses the other sense of the term 'virtual machine'. In this later sense, the hardware and operating system cooperate to allow a single physical machine to host multiple virtual instances of (more or less) the same architecture, in which multiple copies of the whole operating system are written as if they are running on more or less bare hardware. Later, the X86 was designed with features to facilitate this.
So, yes, any virtual machine is making use of some physical hardware, unless you implement it with pieces of paper passed around a table (pace John Searle). But when the virtual machine bears no resemblance to the machine it is running on, then there's no need for special help from the operating system and hardware, and no need for anything as complex as VM/370, or VMware.
If hardware support is a must for virtualization, ...
Let me stop you right there :-)
There is a difference in concept between the JVM (software virtualization) and (for example) a VMWare VM (hardware-assisted virtualization).
The JVM (and other software-based VMMs such as the ones that allow to to emulate x86 on Solaris hardware - I think Bochs and possibly DosBox fall into this category) runs like any other application, using the operating system to gain access to the hardware, or emulating its own hardware purely in software.
VMWare, and the other VMMs optimised for speed, rely on hardware support. In other words, they run on the hardware as if they have full access to the hardware and, only when they try to do something they're not supposed to does the OS captures that attempt and fake it.
That's why VMWare runs so much faster than the software-only emulators. It's because, for the vast majority of the time, it's actually running on the real hardware.
The JVM is a virtual machine, but it doesn't require any additional support from the Operating System. Instead of virtualising instructions for a particular CPU it executes java bytecode.
The JVM is a virtual machine for running Java, in other words it emulates a machine which would be capable of running java. It is a confusing choice of names, but it comes from the general meaning of "machine" not from the more common Virtual Machine meaning.
The JVM, like a regular VM emulates the execution of instructions, but in the case of the JVM the instructions being emulated are Java Instructions, and in the case of a VM they are Hardware Instructions as would be executed by an OS running on the same hardware.
Yes the JVM does access hardware, however this is why you install a MAC or WINDOWS JVM since the instructions are translated by the JVM and acted upon depending on the installation of the JVM, for example, open file dialog on mac opens the mac dialog and windows JVM opens the windows dialog.
So its not being virtualized by the system, but the bytecode is being virtualized by the JVM you installed. It's basically like an application that reads something(bytecode) and does something(access hardware, or other stuff).
It should be noted that nothing stipulates that a JVM does not (have to) have HW virtualization access. There are notable exceptions, but to which the answered poster alluded, few CPs exist that run Java bytecode natively. Maybe someday a Java bytecode HAL or TIMI will be commonplace to put the JVM into the same class as the formalized HW virtualization?
Heres the problem. I use around three different machines for development. My partner is using two. We have to go through the same freaking set up procedure on all five machines to get to work.
Working with a php project here, so:
Install and configure, PDT, a php debugger, and some version of XAMPP.
Then possible install an svn client, and any other tools.
Again, to each of the five machines.
What if, instead, we did all of this once, in a virtual machine that is set up with the same stack, same versions, as the production server. Then each of us could grab a copy of the VM image, run that image on each of the five machines and do all of our development in that VM. Put Eclipse, apache, mysql, the works, all in that vm.
The only negative of this approach, and please correct me on the only part, is performance. Is it really that big of an issue though? The slowest machine out of the five is a Samsung NC10 powered by an Intel Atom 1.6 ghz processor.
Do you think this is possible and practically usable? Or am I crazy?
I use a VM for development (running on my laptop) and have never had performance problems. Another approach that you could take would be to image the drive in the state that you want. Use Acronis or Ghost to re-image each machine when you need to. Only takes about 5-10 minutes to restore an image on any modern PC.
I use a VM for all my "work" as it keeps it away from my "play". This set up allows me to use the office VPN without exposing my whole machine to the office environment (which I trust about as much as the internets. ;-) Also I don't have to worry about messing up my development environment by trying games or other software. My work VM is currently running inside VirtualBox but I have used VMWare in the past. I have only noticed performance issues when using graphic intensive programs like Webex or the Terminal Server Client.
It can certainly be done. What turns me off is the size of the VM image, which would normally be several GBs. Having it on a network share means it can take longer to transfer then your current setup process takes. I guess an external hard drive would be the easiest way to move it around.
Performance wouldn't be an issue with any web development.
I have to ask why your current machines need to be "re-imaged" each time you sit down for work?
If you're using Windows you'll probably want to use SYSPREP on the master image so that the 'mini-setup' runs when you boot up the virtual machines for the first time.
Otherwise in terms of Windows' point of view, the machines have the exact same SID, hostname and other things - running multiple machines with the same SID on the same network can cause tons of headaches. Even more if you want them to communicate with each other.
I've run websphere for zSeries on a vmware virtual machine with no problem and websphere is more resource intensive then any PHP stack. I find that having a multi core machine or at least hyper threading makes it run a lot faster.
With vmware, disk operations are slower. For PHP development I doubt it would be a problem, but you'd definitely notice it if you are compiling a large C++ project. There is also Sun's VirtualBox which is free, and the latest version is rather nice (but I haven't looked at how slow disk operations are yet).
I am using that idea in practice. Virtual machines are generally great for development.
To run on multiple operating systems and multiple separate development environments.
Preserver older development environments for later support.
Can be easily backed up, when hard drive crashes no need to start from beginning.
Can be copied from developer to another, so everyone don't have to do tedious installations and configurations.
Down sides are:
Virtual machines are slower, you need more powerful computers than you would need otherwise. I would recommend having at least 4 G of ram, but preferably more like 16, fast multi core processors and fast hard drives.
Copying Windows OS virtual machines, each used copy of virtual machine should have it's own product key. When you make a copy, it needs to be registered with new product key.
Did you think about a software configuration manager like ansible, chef or puppet? With such software automation of such tasks is very easy! It can even create fresh vm and then configure it.
Is virtual PC practical on a home personal development computer. I do some custom .net programming at home and I was wondering if in terms of performance and overall use, Virtual PC is useful. Do the applications inside Virtual PC session run slower. It will help me with my personal dev machine. Would you recommend any other products?
In my estimation virtual machines are one of the best tools that a developer can have. I have my base dev machine and on it I run VPC for different platforms to test installations and application functionality. For web development I keep VPC;s running each of the major browsers that I support, so I continually test my websites on various browsers. I even still maintain an old VB6 app and I have replicated my old VB6 build environment to a VPC image. Make sure you have lots of RAM. My machine runs with 4GB and that works well for most everything I need. I also have Sourcegear Vault set up for source code management. I have the clients loaded on the various VPC's that I use for development and they all check data in and out from my central SQL Server box. It works great.
It really depends on what your home computer is like. I've used VPC to test different versions of Visual Studio (e.g. to make sure that a solution is VS2005 compatible, and to check out VS2010).
I wouldn't want to use it all the time, but then I am working on a laptop. Given a really meaty multicore home desktop (preferrably with hardware support, of course, and lots of memory) it could be reasonably practical for day-to-day use.
VMWare Player is free and some people find it faster - I haven't used it enough to compare the two properly myself. If you're spend a lot of time "in" the VM, it would probably be worth giving both a proper test-drive.
VPC is a very good choice. I use it to test deployments and for presentation purposes.
If you have a PC with a new Intel chip and at least 2 gigs of RAM it actually works just as fast as a regular PC would :).
I recommend 4 gigs of ram though, they're cheap as hell these days and it really matters.
I've had some success with this; I had to develop some older .NET 1.1 software on Vista, which wasn't supported. I had to run XP in a virtual PC container in order to get the project done.
The biggest issue was available RAM; I'd recommend maxing out your home PC to use as much as it can- this will likely be less than 4GB unless you're running a 64Bit OS. I found that getting an extra gig of ram made life much better. Ram is cheap right now, so I'd start there if it didn't work well enough for me at first.
Yes applications will run slower but the hit isn't as big as you might expect. It is pretty reasonable to do development on a virtual machine. Obviously the performance is relative to how fast your computer is, a mulitcore machine will do nicely.
If you develop driver or core routines, where every mistake can and usually will result in a crash. A VM is the best you can use.
I tried Virtual PC and VMWare. They are both pretty good for such stuff.
Virtual PC should be fast enough, unless your driver or code is really time sensitive. A cross-platform, free alternative to Virtual PC is Virtual box.
If you've got a VirtualPC license already, by all means use it. If not, you might have a look at Sun's VirtualBox. It's Free/Libre and cross-platform. I use it to run windows and linux on mac os x and linux and have been quite happy with it.
You can run your dev tooling natively on your pick of O/S. and use VM's to test on other environments. Get lots of memory if you're going to do this, say 2GB or more - if you haven't already.
AMD chips have some facilities (nested page tables etc.) that improve VM performance. 2nd gen Opterons and some Athlon 64 chips will support this for reasonable money. You can even get brand-name hardware like an HP XW4550 with this sort of chip for fairly reasonable money. I'm not sure to what extent Intel has caught up with this yet.
Assuming your host machine has enough raw power then a virtual machine works fine. I have a 2.5GB ram, 2Ghz duel core work laptop and don't want to install vs2008 for personal development so have a virtual machine for that. I've given it 1 GB of dedicated memory at the moment and it runs great, no problems. If needed I'll up the ram allocation but for now I'm happy.
Hope this helps :-)
I use VirtualBox for all development and find the performance much better than VPC. My machine is about a 2 year old dual core with 4gb ram and performance is not noticeably slower than running natively. The virtual machines are Vista and the host OS is Windows 2008. I would definitely recommend using virtual machines as creating a fresh new machine for a new project is very easy.
I have a toshiba notebook with 2Gig of Ram. I am wondering if its worth to install Virtual box and use it to browse web, do quicken, some small dev work etc.? How would I install Windows OS on virtualbox virtual session? Are there good tutorials out there? Would 2gig of ram be enough to run virtual sessions on notebook computer with following configuration:
2 gig of ram
Intel Pentium 4 cpu
60 gig hdd