Monday, April 16, 2012

Saved By The VM

One of the most exhilarating, but also frustrating, aspects of working in computers is how fast things move. Things that would've been considered disgracefully wasteful years ago, now provide us with solutions that I never would've imagined then. For example the editor that I am using to write this is running inside of my browser. In effect, the browser is acting as a virtual machine, and the editor is just one application running on it. How much CPU "wastage" is there by running in a VM rather than a native application? Who knows, but it doesn't matter, as my laptop isn't even breaking a sweat. And this is just one of dozens of tabs that I have open in the browser, and the browser is just one of over a dozen applications running currently (plus who knows what the OS is doing).

Not only is CPU time cheap, but so is storage. At work, our network storage takes automatic snapshots, which makes it trivial to retrieve from backups. This would've seemed incredibly wasteful to me not that long ago. This, combined with VMs, saved me a ton of work this past week.

Torquebox 2.0.0 was released recently, and I wanted to get it installed on our development server. While I was doing this, I decided to upgrade the version of Java running on the machine. I downloaded the latest version and installed it. Unfortunately, I wasn't paying attention and I let it install in the default location, rather than our group's standard location. In a moment when I was apparently flashing back to the days of yore, I thought I could just move the Java directory structure to the location where I wanted it. Since the registry settings did not get updated in the process, bad things happened. My first attempt to fix things was to just delete the Java directories, and reinstall it. Unfortunately, Java thought it was still installed, and refused to reinstall. So then I asked Windows to uninstall Java, but a DLL was missing (probably because I had already deleted it), so it couldn't uninstall either.

What was I to do? I spent some time fiddling with the Windows Registry, but that was getting me nowhere. Finally, I came to my senses and remembered what year it was. Our servers are running on VMs which means it's just an image on a network disk somewhere, which has regular snapshots taken. So I just wandered down the hall and asked one of our system administrators to restore the VM to an image from the day before. A few minutes later, my mess was cleaned up.

So yes, VMs are wasteful and inefficient, but they sure save time sometimes. And what's all this extra CPU power for, if not to make our lives easier?


Anonymous said...

The first paragraph of your post is interesting, talking about how some things were considered disgracefully wasteful years ago. Usually when I start talking like that my co-workers all remind me I'm the old man in the room. Does that happen often to the Madking these days? :)

Michael Haddox-Schatz said...

My coworkers are my age-ish, so I don't get that at work. But yes, things do come up to remind me that I'm an old man these days. At least in computer years.