CentOS 6 P2V Alternatives?

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Hello all,

This week I’ve tested out a few ways to do a P2V on a rather ancient CentOS
6 server, in order to move it to a Hyper-V host.

So far my tests have failed rather spectacularly. Initially I was set on doing a simple dd-routine, but was told that the server cannot be taken off-line as it’s being used daily, so had to look for other solutions.

The disk setup is currently as follows:

Three 500 GB sata-disks, sda, sdb and sdc, are used to build a software raid called md0. No LVM‘s here.

Sdd is a 120 GB drive, with partitions for boot, swap, home and /. No LVM’s here either.

The farthest I’ve gotten is with the Rear solution. http://relax-and-recover.org/

The backup goes well, but recovery for some reason fails to create initramfs with all the installed kernels, as well as failing with an error saying it cannot find /boot/grub, after which the recovery terminates.

Virtualizing systems like this is kinda’ new to me, having it done on Windows only, and I’m not really sure how to proceed when it’s a CentOS system in question.

The physical CentOS-server runs a few license managers and nfs-shares that server molecular modeling software, that are rather intricately set up (I
inherited this server some fifteen years ago).

Are there any easier ways to do a P2V at all?

8 thoughts on - CentOS 6 P2V Alternatives?

  • Sorin Srbu wrote:
    I think I would try to create a VM that has the physical disks passed through and also has access to whatever storage it´s supposed to reside on once the conversion to a VM is completed. Then copy it from the physical disks to that storage.

    Converting without shutting the machine down is probably not possible. Passing the disks through may give you the advantage that the downtime can be kept to a minimum.

  • How would you recover if that server were suddenly destroyed, let’s say by a power supply failure that fried the motherboard and all the disks? If you can’t bring up a machine on new, bare iron starting with nothing but your backups and a CD or USB stick with a recovery tool, you need to seriously reconsider your backup strategy.


    Bob Nichols “NOSPAM” is really part of my email address.
    Do NOT delete it.

  • Robert Nichols wrote:

    That´s a very good point.

    What options are there to make complete and consistent backups of machines and VMs while they are running? Just shutting down a VM to make a backup is troublesome because you sometimes need to run ‘virsh shutdown xx’ several times for the VM to actually shut down, and I have VMs that do not shut down no matter how often you try. If you manage to shut down the VM, there is no guarantee that it will actually restart when you try — and that goes for non-VMs as well. Shutting them down manually frequently to make backups is not an option, either.

  • Every backup tool that can be run on a physical machine can also be run in the VM. For databases that cannot be simply copied while they are active, there should be a way to generate a snapshot or other consistent representation that can be backed up and restored if necessary, and any database that does not provide such a capability should not be considered suitable for the task at hand. Long-running jobs should always have checkpoints to allow them to be continued should the machine crash. (I have such a job running right now. Coincidentally, it’s verifying the consistency of 3 years of backups that I just reorganized.)

    There is no “one size fits all” answer. The needs of a transaction processing system that can never, ever lose a transaction once it’s been acknowledged are radically different from those of a system that can afford to lose an hours, or days, worth of work.


    Bob Nichols “NOSPAM” is really part of my email address.
    Do NOT delete it.

  • I’ll toss my two cents worth in having dealt with a similar situation recently (well 2015, but close enough).  If this server is /that/
    important, I’d really consider building a completely new virtual instance on the hypervisor of your choice.  Though, to be completely honest, Hyper-V is just awful in my testing. There are far more P2V
    options for VMWare, including it’s own P2V software which I’ve not had particular trouble with in a half-decade, if you insist on a P2V migration.

    If we’re just talking backups, Veeam for Hyper-V  (and ESXi) works really well and you can bring up the backed up VM on the fly if you need to recover data from it, or for DR/BC.  I’ve never had a problem with it and, at my last position, had it set to run the backups on a remote cloud in case of catastrophic damage to the office.  Of course, there’s no such thing as too many backups, so critical data on a server like you have was replicated to a warm/cold site, or part of a cluster for DBs to make sure data integrity was kept and uptime maximized.


    Mark Haney Network Engineer at NeoNova
    919-460-3330 option 1
    mark.haney@neonova.net http://www.neonova.net

  • I touched the physical disk solution briefly while looking around, but felt at the time it was a tad bit complicated.

    I’ll have another look at this.

    Thanks for the feedback!

    //Sorin

  • The important data is backed up properly. I’m looking for a “quick fix” solution to clone the server as is. I’m pretty sure I can duplicate the setup for the license managers and intricate scripts, and what not. I’m just not too hot on spending a few weeks on this.

    I’m aware of the fast – cheap – good pyramid. :-)

  • While Hyper-V is not ideal, it’s good enough for our purpose. We made a choice a few years back to either completely rehaul our vm infrastructure or just hand it over to central IT at our university. The later option won, mostly because of the cost. Since central IT uses Hyper-V, that’s what we also use.

    Building a completely new vm and somehow restore from backup the important parts, is what I’m looking at now.

    Thanks for your feedback!

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