Greetings 
Can you please share your knowledge of pros and cons of qemu and virtualbox?
The structure that I would like to see is the following:
Qemu
Pros
Insert pros here
Cons
Insert cons here
Virtualbox
Pros
Insert pros here
Cons
Insert cons here
This would help beginners like me to decide which one is the best choice!
That being said, let the share of knowledge begin 
Please hold back a little. The subjects youāre touching have already been discussed thousands of times in hundreds of languages. Threads like the ones youāve started here will add nothing to those. And, personally Iām not waiting for YAFWAWS ( Yet Another Flame War About Whatever Subject ), which IMNSHO the average thread re. āvsā, āpros and consā results in in most cases.
Is there at least a thread that shows the main differences between Qemu and Virtualbox?
Does exist a post that explains the main differences between Qemu and Virtualbox for beginners?
Google is your friend, possiblyā¦ 
https://encrypted.google.com/search?hl=en&as_q=Qemu+Virtualbox+comparison
You should understand the comparison as youāve framed it is flawedā¦ comparing completely different things (ie apples and oranges).
You should start with looking up the definitions for each(Wikipedia is a good start).
Virtualbox is a fairly typical ā2nd Genā virtualization technology (ie fundamentally will perform and shares a common architecture with practically all other virtualization technologies except Xen). A major differentiator is that it installs and runs pretty much as a User application which means that by default itās not suitable for āServerā use without modification. With other virtualization technologies, you can deploy as a Server more quickly with fewer tweaks.
Strictly speaking, QEMU today is not its own virtualization technology in the same way we speak of the major vendorsā¦ It used to be, but today has been integrated into both KVM and Xen, enabling both KVM and Xen to support full emulation in special QEMU mode. Full emulation can be considered an important capability because it means that your Guest can think itās running on some other CPU architecture, not the same as the HostOS. Full emulation in the past came with severe performance penalties but very recently enjoys x64 CPU extensions as well, so itās less clear how much of a performance hit happens.
If Iām not being completely clear, IMO QEMU and Virtualbox are too different in so many ways to compare, or the comparison is so starkly different that each is usable only for different purposes. Any comparison of which is better should only be asked when comparing 2 things that are similar enough that either might be considered in the same situation which isnāt whatās happening here.
HTH,
TSU
I donāt really think that we should do all the work for you. The best way for you to arrive at a consensus within yourself is to do some tests, some work.
Whatās that old saying? āKnowledge comes from endeavourā or something like that.
I see that assumptions are being made about me not doing my research, and they are wrong. IMHO http://marciasirotamd.com/psychology-popular-culture/problem-making-assumptions explains well the problem with making assumptions. I did my research, however it was not a good one. Also it would be nice to have a sticky post that explains what is Qemu and Virtualbox in a very simple way. I know that it would be hard work, but a very appreciated one by beginners
Hi
Then my assumption is your research is somewhat flawed?
The openSUSE Documentation would be a good place to start.
https://doc.opensuse.org/documentation/leap/virtualization/html/book.virt/book.virt.html
For Virtualbox, head to the documentation at Oracle, again, seems a no brainer?
As a ābeginning to need to use Virtual Machinesā user, it may help to first decide why one wishes to use a Virtual Machine.
If the āwhyā is, to run another operating system on a Linux platform then, the choice narrows down to āwhich VM product provides the best support for the wished for configurationā. For example, running the Redmond thing in a VM on a Linux platform is not easy and, the choice of āwhich VM product to useā is also not easy . . .
If on the other hand, the āwhyā is, to run Linux instances in VMs on a Linux platform, the choices are many and, thereās no ābest choiceā ā it comes down to āwhich VM product is the easiest to manage from the point of view of the human beings involvedā.
I already said that my research was not good enough.
Thank you for sharing the link.
Please be polite with other people. It is a important behavior for a healthy community.
I already said that my research was not good.
Thank you for sharing the link.
Please be polite with other people. It is a important behavior to a healthy community.
Please be aware that, weāre not sales people and therefore, weāre quite careful about recommending any given VM product for a given situation.
Yes, some of us regularly use VMs and, we have our personal preferences but, whether or not a particular product will fit the needs of someone else, is something which would be, probably, difficult to define.
Please be more explicit about your needs with respect to VMs and then, possibly, some hints as to a possible choice can be given.
[HR][/HR]Yes, VirtualBox is open source but, Oracle is the master and therefore . . .
Please try to understand what is going on here when you ask a question. Any question.
There is a group of openSUSE users that volunteer in their spare time, will look at your thread title. They then will decide if it might be something to open and read. This decision depends completely upon the title and the volunteers mood at that moment in time. And that process is repeated in every following step: the volunteer decides if (s)he has interest and knowledge in the thread. When not (s)he goes for another thread of for a beer or for whatever.
To begin with, many people even never look in Soapbox because they think that serious technical questions are moer of their liking. Nevertheless a few hundred people openen your thread, but then decided that they lack the knowledge or do not want to be involved in a product a vs. product b discussion.
After 24 hours one of the mods tried to explain to you that the openSUSE forums might not be the best place to have such a discussion. Others went then so far to point you to other places on the Internet. Most of the posts point clearly in the direction: you will not get an answer to your liking here and I do not want to get involved, better go elsewhere.
You refused to understand these hints and went on putting pressure on people that as volunteers do not want to be pressed at all. They want to be free to join or leave a discussion.
My conclusion, do not be amazed when the hints start to become a bit more clear. And categorizing them as incorrect behavior is likely to have more and more people here ignoring all you post.
So please take the advice you got here as the maximum you will get.
Thank you for the advice 
Sorry everyone for my misbehavior 
Thanks for your reaction.
Please, take this as case closed. Whenever you have a technical problem with openSUSE, do not hesitate to ask in these forums. People will try to help you. Most of them are really happy when they can help others with the knowledge and experience they gathered in running openSUSE.
Weāre all convinced of that. But weāre also experienced in seeing where discussions can go, weāre also here to guide new users, incl. reasoning them away from faulty assumptions. And one of the most valuable advices we could give is: āTry them, use what suits you bestā.
Some advice: Donāt start with complex matters like virtualization. Start using one or two desktop environments, for daily routines like browsing, email, Libreoffice and get some kind of āhomeā feeling with it. Re. virtualization: if you lack knowledge, start with Virtualbox, qemu is a completely different beast.
Questions of this type are asked quite often in the virtualization forum but should be typically framed differently, so instead of the more general question you asked, you might have considered something like
For my first virtualization, I donāt understand which I should choose, Virtualbox or KVM/QEMU or Xen/QEMU?
Iām learning virtualization, is Virtualbox or KVM/QEMU good for beginners?
Or, something like
Iām considering virtualization to do <ā¦>, and am considering Virtualbox or KVM/QEMU. is one better than the other?
Or, maybe
Iām considering installing Virtualbox on my system, how should I do that?
Iām considering installing KVM/QEMU on my system, how should I do that?
Even
Iām trying to choose between Virtualbox and KVM/QEMU, can I install both on my system and try them both out on the same system?
The above questions have all been asked over the years in the Virtualization Forum, you can search for what has been asked and answered before, and if you think the discussion was too old and might want to ask for an up to date answer, then post and state that reason for asking the question again.
https://forums.opensuse.org/forumdisplay.php/934-Virtualization
Youāll notice that the question examples above arenāt general āWhich is best?ā because thereās a lot of subjectivity (Individual opinion) as well as factual features which can be considered. Instead, narrow your question to fit a specific purpose or use you have in mind, or a specific unanswered question you need answered.
HTH,
TSU
The reference link to openSUSE documentation only covers a tiny piece of all virtualization, especially from the 30,000 foot levelā¦ Only
KVM
Xen
LXC containers (which isnāt really virtualization although we discuss as a common category)
So,
The reference can be helpful to learning about the three specific technologies listed above but covers no ground for any of the other major virtualization Vendors (eg Virtualbox, VMware, Hyper-V, Parallels), isolation vendors(eg Docker, LXD), Enterprise Management(eg OpenStack) and minor(today) vendors which can include specific cloud PAAS(ie VPS), OpenVZ, Kubernetes, moreā¦
In other words,
Donāt hesitate to see what is in past Virtualization Forum discussionsā¦
And, there is almost no condemnation of misbehavior (although Iāve personally drawn a line at answering the same exact question more that 3 ways in the same forum thread).
TSU