[clug] Seeking FOSS Hypervisor and Management GUI

[Bob Edwards]

On 01/10/14 13:32, George at Clug wrote:
>      I really hate showing my ignorance, I had to look up what dd was;
> The dd command copies a file, converting [1] the format of the data in
> the process, according to the operands [2] specified.
>
> Snapshots have an advantage over "copies" of a virtual machine,
> especially when that virtual machine is a data repository that is
> larger than the free space (even when compressed) on the host
> hypervisor. And 6TB of data takes a while to copy, dd, etc.  A
> snapshot should just fork any new changes to the original image for
> the life of the snapshot, consolidation is the process of merging the
> snapshot changes back into the original image.  If the snapshot is
> not too old, both of these tasks are usually are very quick.  At
> least that is how I understand the VM snapshot process.
>

That's all true.

I was thinking of just backing-up/copying the system area, not the
entire data repository, which should be backed up elsewhere. I suppose
the updates you want to apply might break the data repository, in
which case you could restore it from backup. But that would take
very many hours...

Cheers,

Bob Edwards.

> http://www.computerhope.com/unix/dd.htm
>
>
> Create a ISO disc image [3] from the CD in the computer.
>
>
> dd if=/dev/sr0 of=/home/hope/exampleCD.iso bs=2048 conv=noerror,sync
>
> To be honest most of my VMs range from 500GB to 3TB, but could grow to
> 9TB quite easily, so I like to have a solution that can support into
> the future.
>
> Thank you for your comments. An old saying that I rather like is
> "_there is more than one way to skin a cat_", even if I am a cat lover
> who believes the best way is "not to skin a cat at all".
>
>
>
>
>
>   Of course, "snapshots", as you are wanting to use them, are just a
> "convenience".
>
> You can almost as easily just shutdown your VM when it is good, run dd
> etc. into gzip to get a copy of the VM disk image, then start it back
> up and go ahead and break it.
>
> When you want the original back, just gunzip and dd the saved image
> back over the broken VM filesystem and you effectively have the same
> result as a snapshot...
>
> Do it again and again, until you get bored...
>
> Script it all up, for more convenience...
>
> Cheers,
>
> Bob Edwards.
> ttps://lists.samba.org/mailman/listinfo/linux [4]
>
>
>
> Links:
> ------
> [1] http://www.computerhope.com/jargon/c/conversi.htm
> [2] http://www.computerhope.com/jargon/o/operand.htm
> [3] http://www.computerhope.com/jargon/i/isoimage.htm
> [4] https://lists.samba.org/mailman/listinfo/linux
>