Will installing 10.6 as a VM mess up my real 10.6 install?

[Ctein]

Dear Folks,

Before upgrading to Lion, I need to confirm that my (Rosetta-based) business-critical apps and peripheral drivers will run correctly in the virtual OS. So I want to set up a virtual10.6 under VMWare 4.1  as a test bed on my system that is currently running 10.6.8. If all works well, I can then upgrade my "real" OS to Lion.

When I launch the virtualized Mac OSX installer, the only destination disk it shows me for installing the Virtual 10.6 is my "real" system disk (a.k.a "Macintosh HD"). I *assume* that's just a virtual destination and that the installer-running-under-VMware isn't actully going to attempt to install a new copy of 10.6 over my existing real OSX installation.

Is that right? I'd like confirmation before I act on my assumption and discover I've "bricked" my machine.

Thanks for the hand-holding.

pax / Ctein

[dariusd · Accepted solution]

Hi Ctein,

If you have created your virtual machine in the regular way (without any advanced disk configuration), the virtual machine will have a 40 GB virtual disk pre-labeled "Macintosh HD" which is isolated from the host's disk, so that you can install into that virtual disk from inside the guest, without overwriting your existing 10.6.8 system.

If you'd like to confirm this, check the disk capacity information on the screen inside the virtual machine where the installer asks you to select the destination disk: The virtual disk's capacity will generally be shown as about 40 GB, almost all of which will be free space, while your host will generally have a significantly larger disk, of which a larger part will already be used.

For comparison, upon installing Snow Leopard (10.6.0) into a fresh virtual machine here (my host system is a Mac Pro with a 500GB hard disk), the installer inside the virtual machine sees only its 40-ish GB virtual disk:

   Macintosh HD

   At least 42.55 GB free

   42.61 GB total

If you are seeing the same numbers when you install, it's a fairly safe bet that you're installing into a nice, compartmentalized virtual disk, isolated from your host's Macintosh HD.  If the numbers are wildly different from that, or if the installer actually says anything to suggest that it's going to overwrite an existing installation, you should double-check before proceeding!

Having said that, it's always a good idea to have backups, particularly if you have business-critical stuff floating around...

Cheers,

--

Darius

[Ctein]

Dear Darius,

Ah, a sample sanity check.  Yes. Thanks!

FWIW, when one hits the "choose your hard disk" stage, VMWare has only created about 3GB of virtual disk, but that's sufficient to identify where the data's going (in my case, I keep my virtual machines in a different volume than my real OS).

Backups, oh yeah. Always, both personal and business. I remember buying my first PC long ago in another galaxy and having to argue with the salesperson to get a tape drive installed in it, so I could do proper backups.

I've never suffered a catastrophic data failure, but those backups have saved small amounts of my bacon so many times...

        pax / Ctein
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