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I've been a trainee in company for a month, and my mission is to migrate 3 physical servers to a virtualization technology. The company edits software for E-learning so there are lots of data like videos, flash and compressed (zip).

This is a part of the servers inventory: OS: Debian, 2 redhat, apache, php/mysql, sendMail/Dovecot, webmin with virtualmin template to create dynamically the web sites because there is no sysadmin ... The future provider will be responsible of to secure, update and create the virtual machines (outsourcing) and with a RedHat OS's.

So i want some help to choose a virtualization technology (I prefer KVM of Redhat RHEV, VMWare is expensive), how to evaluate the hardware needs (this for evolution of 4 or 5 years) and to elaborate a good plan so I don't forget anything.

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Well, hat about starting with the SIMPLE realization that this is NOT A FORUM? – TomTom Jan 9 '11 at 7:45

If you want to take a physical server and convert it into a virtual server, you'll want to google for Physical to Virtual Migration (P2V). There are tools available like the VMWare converter that will migrate the server, mostly in an automated fashion.

The methods for P2V depend a lot on what you're going to use. VMWare ESXi is free, and works well for small businesses or businesses that can have a person dedicated to working on keeping the limitations of ESXi from killing their server availability (there aren't a lot of limitations, but the ones there are are significant, like no live migration). ESXi is great when you don't need to worry about 24/7 availability of the servers for things like backing up VM images (I normally shut them down and copy off the server, but there alternative approaches like using a normal backup solution to back up the virtual system as if it were a physical server and restore by building a virtual server blank and restore from virtual bare metal; many do a combination of these techniques since copying the drive images for our servers takes most of a weekend but can simplify recovery by just copying it to a new server and pointing a new machine to boot from those images).

Other platforms will have their own tools, or you may opt to just rebuild the servers from "virtually" scratch.

If you're talking about migration planning, I'm not sure what exactly you're aiming would probably be better off asking about individual servers, since email can have separate considerations from an SQL database, like monitoring DNS entries. General considerations for VM's in general would be things like conversion issues (will it see the network card properly, manually having to set the IP, take the physical off the network before firing up the VM so there's no collision of IP or name...) and some of those considerations would depend on what solution you're using; what is an issue with migrating to VMWare may not apply to KVM.

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For straight virtualization I would suggest VMWare: ESXi is free if you don't need any of the advanced features (high availability, cluster management, etc.), and if you need those features VMWare has them developed, tested & supported, which IMHO is totally worth the licensing and support fees.
As an added bonus VMWare virtualization looks like physical hardware to the OS, so your "future provider" won't have to worry about any strangeness/"virtualization leakage" that can be introduced by other technologies.

As far as actually getting your systems into the virtual environment, VMware supplies the VMWare Converter tools to simplify direct Physical-to-Virtual migrations, but a virtualization project is a great time to look at your system architecture and determine if there are any changes you would like to make.

Re: your project as described above, was this just dumped into your lap or do you have some guidance/help from above? Generally speaking I wouldn't consider virtualizing an environment as a task for a "trainee"(intern, jr. admin, etc.) unless they were getting some help in the process.
Among the stuff you mentioned above, picking hardware is particularly important (getting an idea of the kind of disk bandwidth you'll need, how much RAM you'll need, what the CPU load is going to look like and whether or not reservations should be made for specific machines/classes of machines (i.e. configuring "resource pools" in VMWare's terms).

Getting that kind of stuff right is especially important if you intend this hardware to live out its entire useful life cycle while still providing what your clients would consider good performance, and just going based on the fact that you're a "trainee" I would suggest working with someone familiar with your environment who has the experience doing profiling & the instincts to spot performance bottlenecks so you don't wind up with any unanticipated problems.

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Hi djoudi I am doing some thing similar which you asked here.(This includes sysadmin+video flash work) I recently tried Vmware converter for a stuff similar to you have. If you plan to use Vmware converter which is free for Linux then when you are giving IP and login etc details of the server which you would like to convert to virtual the Vmware convert tool will ask you to give the IP of VMware server which I think in your case you do not have.As others suggested Vmware things are worth the price. But in your case if Vmware is not applicable then I would say to go for installation of Red Hat KVM and use its gui (virt-manager) on a server different than your production machine.Let us call this staging server.You will do your experiments here.

Once you are done with installation of virtual machines on this intermediate server then what you need to do is do an rsync of physical server(which you wanted to virtualize) to the Virtual Machines running on intermediate server this can be as good as cp -r just make sure you are following same sort of partitioning scheme on your Virtual Machines as well in that case even if you do cp -r that will also do.

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