[clug] Seeking FOSS Hypervisor and Management GUI
George at Clug
Clug at goproject.info
Tue Sep 30 21:32:14 MDT 2014
I really hate showing my ignorance, I had to look up what dd was;
The dd command copies a file, converting  the format of the data in
the process, according to the operands  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.
Create a ISO disc image  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
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
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...
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