On Sun, Oct 21, 2012 at 2:39 PM, Greg Freemyer wrote:

On Sun, Oct 21, 2012 at 3:30 AM, ellanios82 wrote:

...

Hello SuSErs

Virtual Machines _______________

Could it make sense to PREFER to run Linux as a Virtual Machine?? { thus, for example, one might install openSuSE 12.2 as ones foundation, and Next, install a Virtual Machine, then, Finally install another instance of openSuSE 12.2 on ones Virtual Machine upon which Virtual Machine one would do ALL ones work}

thanks

best regards Ellan

The instant VM snapshots do NOT make redundant copies of the data. Thus

- instant backups protect from user errors, etc.

- do NOT protect from hardware failure

So it depends why you're making backups. I would say many of us worry about disk failures, etc. For that you need to get your full backup onto alternate media.

When I first started developing software, my thesis supervisor told me I should always aim to make my software idiot-proof since I can never know what kind of idiot is using it. When it comes to statistics, that could never be more true, given how often I have seen even full professors recommend the wrong statistical analysis. It takes a lot of effort to design your software to protect users against innocent mistakes, but you can't always protect them from 'stupid' syndrome. But I digress. It seems to me that such VM snapshots, taken immediately prior to installing new software (particularly from a source with which one has limited experience, is a good precaution against installation script that behave badly (ever seen the chaos wrought by a bad one of those?). Similarly, taken on a regular basis it serves to protect against PEBKAC. A colleague of mine protected his team against just such a thing by configuring automatic backups: a new team member wrote a badly behaved customer program that not only produced nonsensical results, it over-wrote the original data which had cost many tens of millions of dollars to collect (the fool responsible ended up teaching statistics at a midwestern US college that deserves to be un-named). When my colleague got a panicked call in the early hours of the morning while he was on the other side of the planet, he looked at the results the bozo produced, his program program and made his diagnosis; and then told his team how to recover the original data from the backups, and then he did the analysis that the other fellow was supposed to do but who messed up so badly. he also advised against trusting the bozo with anything of real value - put him where he can do no further harm. Had he used a VM snapshot, though, recovery of the data would have been much, much simpler and faster. That said, since such a snapshot is just a (very large) file, it can easily be copied to a CD or DVD (better, multiple such disks, ultimately stored in different locations) What would worry me is that someone might get the notion that such a thing is a magic bullet. As you pointed out, it has both its uses and limitations, and thus can only be part of a systemati, comprehensive design, involving multiple elements, such as a decent RAID (perhaps using hot swappable SSDs, tape or optial backup media, rationally designed user permissions, redundant servers, &c., &c., &c. To the OP, I would give a qualified affirmative answer, but advise not to forget all the many other aspects of security: system, data, &c. Cheers Ted -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org

JC Francois said the following on 10/22/2012 05:11 AM:

If the idea is to make the system "fool proof" and enable the user to roll back some changes then the btrfs files system is something you should look at.

The same is true of LVM, which is mature. As people have pointed out, if you are suing RAID, then LVM is a very good way to manage file systems. -- To mathematicians, solutions mean finding the answers. But to chemists, solutions are things that are still all mixed up. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org

Adam Tauno Williams said the following on 10/24/2012 10:06 AM:

These same properties can be acquired without a virtual machine. LVM provides snapshots, and btrfs provides snapshots. I've been using LVM snapshots of data directories for years, it works great.

+1 Bother LVM and BtrFS offer other advantages and facilities depending on your context. -- The universe we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil and no good, nothing but blind pitiless indifference. -- Richard Dawkins, River Out of Eden: A Darwinian View of Life (1995), quoted from Victor J. Stenger, Has Science Found God? (2001) -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org